Mapi within a windows service

Hi All,
I wonder if anyone can help me out. I'm currently creating windows
service (32bit) using the MapiStubLibrary and Outlook 2010 headers
within Visual C++ 2010.
Now, this all works fine if I call the MAPI code from within the main
function (i.e. before the service pieces have taken over); this works
whether run as a service or as a command line.
If I call this same code from within the ServiceMain function then it
fails everytime with MAPI_E_LOGON_FAILED from MAPILogonEx.

The function I am calling with all the mapi code within it is as
follows.
thanks for any advice.
cheers
Bruce

int CEnveloperMapi::testMapi(Helper thehelper, char *szMapiProfile)
{
mapihelper = thehelper;


HRESULT hr = S_OK;

MAPIINIT_0 MAPIINIT= { 0, MAPI_MULTITHREAD_NOTIFICATIONS |
MAPI_NT_SERVICE};

hr = MAPIInitialize (&MAPIINIT);
if(hr == S_OK )
{ // IMAPISession Smart Pointer Context
CComPtr<IMAPISession> spSession;

hr = MAPILogonEx(NULL, szMapiProfile, NULL, MAPI_NT_SERVICE,
&spSession);

if(hr == S_OK)
{
ListStoresTable(spSession);
} else
{
mapihelper.WriteToLog("MapiLogonEx Failed");

switch(hr)
{
case MAPI_E_LOGON_FAILED : { mapihelper.WriteToLog("MapiLogonEx
Failed - MAPI_E_LOGON_FAILED"); break;};
case MAPI_E_TIMEOUT : { mapihelper.WriteToLog("MapiLogonEx Failed
- MAPI_E_TIMEOUT"); break;};
case MAPI_E_USER_CANCEL : { mapihelper.WriteToLog("MapiLogonEx
Failed - MAPI_E_USER_CANCEL"); break;};
case MAPI_E_NO_SUPPORT : { mapihelper.WriteToLog("MapiLogonEx
Failed - MAPI_E_NO_SUPPORT"); break;};
case NULL : { mapihelper.WriteToLog("MapiLogonEx - NULL result");
break;};
default : {
char shr[] = "0x999";
_ltoa(hr,shr,16);
char msg1[64] = "MapiLogonEx unknown failure [ ";
char *cat = strcat(msg1, shr);
mapihelper.WriteToLog(cat, "]");
break;
};
}
}
} else
{
switch(hr)
{
case MAPI_E_INVALID_PARAMETER :
{ mapihelper.WriteToLog("MapiInitialize Failed -
MAPI_E_INVALID_PARAMETER"); break;};
case MAPI_E_TOO_COMPLEX : { mapihelper.WriteToLog("MapiInitialize
MAPI_E_TOO_COMPLEX"); break;};
case MAPI_E_UNKNOWN_FLAGS : { mapihelper.WriteToLog("MapiInitialize
MAPI_E_UNKNOWN_FLAGS"); break;};
case MAPI_E_VERSION : { mapihelper.WriteToLog("MapiInitialize
MAPI_E_VERSION"); break;};
case MAPI_E_SESSION_LIMIT : { mapihelper.WriteToLog("MapiInitialize
MAPI_E_SESSION_LIMIT"); break;};
case MAPI_E_NOT_ENOUGH_RESOURCES :
{ mapihelper.WriteToLog("MapiInitialize MAPI_E_NOT_ENOUGH_RESOURCES");
break;};
case MAPI_E_INVALID_OBJECT :
{ mapihelper.WriteToLog("MapiInitialize MAPI_E_INVALID_OBJECT");
break;};
case MAPI_E_NOT_INITIALIZED :
{ mapihelper.WriteToLog("MapiInitialize MAPI_E_NOT_INITIALIZED");
break;};
case NULL : { mapihelper.WriteToLog("MapiInitialize NULL");
break;};
default : {
char shr[] = "0x999";
_ltoa(hr,shr,16);
char msg1[64] = "MapiInitialize unknown failure [ ";
char *cat = strcat(msg1, shr);
mapihelper.WriteToLog(cat, "]");
break;
};
}
}

MAPIUninitialize();


return 0;
}