diff --git a/dlls/mapi32/mapi32_main.c b/dlls/mapi32/mapi32_main.c
index 85960456b5f..c0363fb2d91 100644
--- a/dlls/mapi32/mapi32_main.c
+++ b/dlls/mapi32/mapi32_main.c
@@ -25,6 +25,7 @@
 #include "winerror.h"
 #include "objbase.h"
 #include "mapix.h"
+#include "mapi.h"
 #include "wine/debug.h"
 
 WINE_DEFAULT_DEBUG_CHANNEL(mapi);
diff --git a/dlls/mapi32/sendmail.c b/dlls/mapi32/sendmail.c
index 3d9c545798b..9a86b794d65 100644
--- a/dlls/mapi32/sendmail.c
+++ b/dlls/mapi32/sendmail.c
@@ -56,7 +56,7 @@ WINE_DEFAULT_DEBUG_CHANNEL(mapi);
  * NOTES
  *  This is a temporary hack. 
  */
-ULONG WINAPI MAPISendMail( LHANDLE session, ULONG uiparam,
+ULONG WINAPI MAPISendMail( LHANDLE session, ULONG_PTR uiparam,
     lpMapiMessage message, FLAGS flags, ULONG reserved )
 {
     ULONG ret = MAPI_E_FAILURE;
diff --git a/include/mapi.h b/include/mapi.h
index 79591ef92a5..17b20be22fe 100644
--- a/include/mapi.h
+++ b/include/mapi.h
@@ -31,7 +31,11 @@ typedef unsigned long           LHANDLE, *LPLHANDLE;
 #endif
 #define lhSessionNull           ((LHANDLE)0)
 
+#ifndef WINE_FLAGS_DEFINED
+#define WINE_FLAGS_DEFINED
 typedef unsigned long           FLAGS;
+#endif
+typedef unsigned long*          LPULONG;
 
 typedef struct
 {
@@ -79,7 +83,10 @@ typedef struct
 
 /* Error codes */
 
-#define SUCCESS_SUCCESS                 0
+#ifndef SUCCESS_SUCCESS
+#define SUCCESS_SUCCESS                 0L
+#endif
+
 #define MAPI_USER_ABORT                 1
 #define MAPI_E_USER_ABORT               MAPI_USER_ABORT
 #define MAPI_E_FAILURE                  2
@@ -112,11 +119,21 @@ typedef struct
 
 /* MAPILogon */
 
+#ifndef MAPI_LOGON_UI
 #define MAPI_LOGON_UI           0x00000001
-#define MAPI_PASSWORD_UI        0x00020000
+#endif
+#ifndef MAPI_NEW_SESSION
 #define MAPI_NEW_SESSION        0x00000002
-#define MAPI_FORCE_DOWNLOAD     0x00001000
+#endif
+#ifndef MAPI_EXTENDED
 #define MAPI_EXTENDED           0x00000020
+#endif
+#ifndef MAPI_FORCE_DOWNLOAD
+#define MAPI_FORCE_DOWNLOAD     0x00001000
+#endif
+#ifndef MAPI_PASSWORD_UI
+#define MAPI_PASSWORD_UI        0x00020000
+#endif
 
 
 /* MAPISendMail */
@@ -124,6 +141,59 @@ typedef struct
 #define MAPI_DIALOG             0x00000008
 
 
+/* API typedefs and prototypes */
+
+typedef ULONG (WINAPI MAPIADDRESS)(LHANDLE,ULONG_PTR,LPSTR,ULONG,LPSTR,ULONG,lpMapiRecipDesc,FLAGS,ULONG,LPULONG,lpMapiRecipDesc*);
+typedef MAPIADDRESS *LPMAPIADDRESS;
+MAPIADDRESS MAPIAddress;
+
+typedef ULONG (WINAPI MAPIDELETEMAIL)(LHANDLE,ULONG_PTR,LPSTR,FLAGS,ULONG);
+typedef MAPIDELETEMAIL *LPMAPIDELETEMAIL;
+MAPIDELETEMAIL MAPIDeleteMail;
+
+typedef ULONG (WINAPI MAPIDETAILS)(LHANDLE,ULONG_PTR,lpMapiRecipDesc,FLAGS,ULONG);
+typedef MAPIDETAILS *LPMAPIDETAILS;
+MAPIDETAILS MAPIDetails;
+
+typedef ULONG (WINAPI MAPIFINDNEXT)(LHANDLE,ULONG_PTR,LPSTR,LPSTR,FLAGS,ULONG,LPSTR);
+typedef MAPIFINDNEXT *LPMAPIFINDNEXT;
+MAPIFINDNEXT MAPIFindNext;
+
+#ifndef MAPIFREEBUFFER_DEFINED
+#define MAPIFREEBUFFER_DEFINED
+typedef ULONG (WINAPI MAPIFREEBUFFER)(LPVOID);
+typedef MAPIFREEBUFFER *LPMAPIFREEBUFFER;
+MAPIFREEBUFFER MAPIFreeBuffer;
+#endif
+
+typedef ULONG (WINAPI MAPILOGOFF)(LHANDLE,ULONG_PTR,FLAGS,ULONG);
+typedef MAPILOGOFF *LPMAPILOGOFF;
+MAPILOGOFF MAPILogoff;
+
+typedef ULONG (WINAPI MAPILOGON)(ULONG_PTR,LPSTR,LPSTR,FLAGS,ULONG,LPLHANDLE);
+typedef MAPILOGON *LPMAPILOGON;
+MAPILOGON MAPILogon;
+
+typedef ULONG (WINAPI MAPIREADMAIL)(LHANDLE,ULONG_PTR,LPSTR,FLAGS,ULONG,lpMapiMessage);
+typedef MAPIREADMAIL *LPMAPIREADMAIL;
+MAPIREADMAIL MAPIReadMail;
+
+typedef ULONG (WINAPI MAPIRESOLVENAME)(LHANDLE,ULONG_PTR,LPSTR,FLAGS,ULONG,lpMapiRecipDesc*);
+typedef MAPIRESOLVENAME *LPMAPIRESOLVENAME;
+MAPIRESOLVENAME MAPIResolveName;
+
+typedef ULONG (WINAPI MAPISAVEMAIL)(LHANDLE,ULONG_PTR,lpMapiMessage,FLAGS,ULONG,LPSTR);
+typedef MAPISAVEMAIL *LPMAPISAVEMAIL;
+MAPISAVEMAIL MAPISaveMail;
+
+typedef ULONG (WINAPI MAPISENDDOCUMENTS)(ULONG_PTR,LPSTR,LPSTR,LPSTR,ULONG);
+typedef MAPISENDDOCUMENTS *LPMAPISENDDOCUMENTS;
+MAPISENDDOCUMENTS MAPISendDocuments;
+
+typedef ULONG (WINAPI MAPISENDMAIL)(LHANDLE,ULONG_PTR,lpMapiMessage,FLAGS,ULONG);
+typedef MAPISENDMAIL *LPMAPI;
+MAPISENDMAIL MAPISendMail;
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/include/mapix.h b/include/mapix.h
index 5300b3bd778..99cbd75d289 100644
--- a/include/mapix.h
+++ b/include/mapix.h
@@ -42,20 +42,33 @@ typedef struct IMsgServiceAdmin IMsgServiceAdmin;
 typedef IMsgServiceAdmin *LPSERVICEADMIN;
 typedef struct IMAPISession *LPMAPISESSION;
 
-typedef unsigned long FLAGS;
+#ifndef WINE_FLAGS_DEFINED
+#define WINE_FLAGS_DEFINED
+typedef unsigned long           FLAGS;
+#endif
 
 /* Flags for MAPILogon and MAPILogonEx */
-#define MAPI_LOGON_UI          0x000001
-#define MAPI_NEW_SESSION       0x000002
-#define MAPI_EXTENDED          0x000020
-#define MAPI_FORCE_DOWNLOAD    0x001000
-#define MAPI_PASSWORD_UI       0x020000
-#define MAPI_ALLOW_OTHERS      0x000008
-#define MAPI_EXPLICIT_PROFILE  0x000010
-#define MAPI_SERVICE_UI_ALWAYS 0x002000
-#define MAPI_NO_MAIL           0x008000
-#define MAPI_NT_SERVICE        0x010000
-#define MAPI_TIMEOUT_SHORT     0x100000
+#ifndef MAPI_LOGON_UI
+#define MAPI_LOGON_UI           0x00000001
+#endif
+#ifndef MAPI_NEW_SESSION
+#define MAPI_NEW_SESSION        0x00000002
+#endif
+#define MAPI_ALLOW_OTHERS       0x00000008
+#define MAPI_EXPLICIT_PROFILE   0x00000010
+#ifndef MAPI_EXTENDED
+#define MAPI_EXTENDED           0x00000020
+#endif
+#ifndef MAPI_FORCE_DOWNLOAD
+#define MAPI_FORCE_DOWNLOAD     0x00001000
+#endif
+#ifndef MAPI_PASSWORD_UI
+#define MAPI_PASSWORD_UI        0x00020000
+#endif
+#define MAPI_SERVICE_UI_ALWAYS  0x00002000
+#define MAPI_NO_MAIL            0x00008000
+#define MAPI_NT_SERVICE         0x00010000
+#define MAPI_TIMEOUT_SHORT      0x00100000
 
 #define MAPI_SIMPLE_DEFAULT  (MAPI_LOGON_UI|MAPI_ALLOW_OTHERS|MAPI_FORCE_DOWNLOAD)
 #define MAPI_SIMPLE_EXPLICIT (MAPI_NEW_SESSION|MAPI_EXPLICIT_PROFILE|MAPI_FORCE_DOWNLOAD)
@@ -94,9 +107,12 @@ typedef SCODE (WINAPI MAPIALLOCATEMORE)(ULONG,LPVOID,LPVOID*);
 typedef MAPIALLOCATEMORE *LPMAPIALLOCATEMORE;
 MAPIALLOCATEMORE MAPIAllocateMore;
 
+#ifndef MAPIFREEBUFFER_DEFINED
+#define MAPIFREEBUFFER_DEFINED
 typedef ULONG (WINAPI MAPIFREEBUFFER)(LPVOID);
 typedef MAPIFREEBUFFER *LPMAPIFREEBUFFER;
 MAPIFREEBUFFER MAPIFreeBuffer;
+#endif
 
 /*****************************************************************************
  * IMAPISession interface