MAPI and Outlook address book - visual-studio

Question

I'm developing one project using VC++ (MSDEV 2008), which has one function to send EMAIL with some attachments. I used MAPI functions to achieve this task.
I build the project with project setting "Character set: use Unicode character set" for UNICODE compatible support and file type is EXE extension. Here everything works fine.
Same project I build as OCX file extension. And I can display "new send mail" window with some attachments. Here the problem is
When I click address book icon ("To" button) to select the receiver mail id from the list. It displays the Address book dialog with title only "S" instead "Select Name: *". But this also works fine in EXE project.
Code:
HWND hWnd = this->GetSafeHwnd();
MAPIINIT_0 tMapInit = { 0, MAPI_MULTITHREAD_NOTIFICATIONS };
HRESULT hResult = MAPIInitialize( &tMapInit );
HMODULE hMapiMod = LoadLibrary(_T("mapi32.dll"));
ProcMapiLogon = (LPMAPILOGON)GetProcAddress( hMapiMod, "MAPILogon" );
(ProcMapiLogon)( (ULONG)hWnd, NULL, NULL, MAPI_LOGON_UI | MAPI_NEW_SESSION, 0, &hCurrentSession );
LPMAPISENDMAIL ProcMapiSendMail = NULL;
ProcMapiSendMail = (LPMAPISENDMAIL)GetProcAddress(hMapiMod, "MAPISendMail");
(ProcMapiSendMail)(hCurrentSession, (ULONG)hWnd, &myMsg, MAPI_DIALOG | MAPI_LOGON__UI, 0);
The question is why Address Book dialog’s title shows only “S” in OCX project. Same it works in exe project.
Kindly help me how to resolve the issue.
Additional note:
Thanks for your reply.
With Simple MAPI code, everything works fine (means I can display new send mail window and send it when I click ‘Send” button) except the “Address Book” dialog’s title (caption).
I tried extended MAPI functionalities also. When the project is built as .OCX file extension like “SendMail.ocx” still Address Book dialog’s title shows only “S”.
Extended MAPI Code:
HMODULE hMapiMod = LoadLibrary(_T("mapi32.dll"));
LPMAPISESSION lppSession;
LPMAPILOGONEX ProcMapiLogonEx = NULL;
ProcMapiLogonEx = (LPMAPILOGONEX)GetProcAddress( hMapiMod, "MAPILogonEx" );
ProcMapiLogonEx)( (ULONG)hWnd, NULL, NULL, MAPI_USE_DEFAULT | MAPI_UNICODE | MAPI_EXTENDED | MAPI_LOGON_UI | MAPI_NEW_SESSION, &lppSession );

Answer 1

Simple MAPI is ANSI only. The external MAPI dll has no idea that you complied as Unicode, all it sees is a string that it expects to be 0x0 terminated. Your Unicode (2 byte) strings have 0x0 for each ANSI character and double 0x0 at the end. Hence your string is terminated at the first 0x0.