Sending MMS via MAPI

The following code snippet can place an MMS into MMS Outbox folder and cause the

phone to attempt to send the MMS, but a failure (error message: Unable to send MMS. Your message will remain in Outbox folder.) is reported just after the MMS data connection is established. The native composer can send and receive MMS successfully.

// pointer to folder having PR_CE_IPM_DRAFTS_ENTRYID in message store with
PR_DISPLAY_NAME = "MMS", e.g. drafts folder of MMS account

// This has been retrieved (code not shown)
IMAPIFolder* pfldrDrafts = NULL;

//pointer to message being created
LPMESSAGE pmsg;

//create the message to be sent
hr = pfldrDrafts->CreateMessage(NULL, 0, &pmsg);

//add recipients
SPropValue propRecipient[3];
ZeroMemory(&propRecipient, sizeof(propRecipient));
propRecipient[0].ulPropTag = PR_RECIPIENT_TYPE;
propRecipient[0].Value.l = MAPI_TO;
propRecipient[1].ulPropTag = PR_ADDRTYPE;
propRecipient[1].Value.lpszW = L"MMS"; //originally this is L"SMS", I changed
to MMS to point to MMS account
propRecipient[2].ulPropTag = PR_EMAIL_ADDRESS;
propRecipient[2].Value.lpszW = L"111111"; //recipient phone number
ADRLIST adrlist;
adrlist.cEntries = 1;
adrlist.aEntries[0].cValues = 3;
adrlist.aEntries[0].rgPropVals = (LPSPropValue)(&propRecipient);
hr = pmsg->ModifyRecipients(MODRECIP_ADD, &adrlist);

//change other properties
SPropValue props[4];
ZeroMemory(&props, sizeof(props));

//PR_SUBJECT points to MMS contents. For simplicity, the MMS body and attachments

(pictures, audio has not yet been set)
props[0].ulPropTag = PR_SUBJECT;
props[0].Value.lpszW = L"Hello World"; //message subject

//mark message as being sent out
props[1].ulPropTag = PR_MSG_STATUS;
props[1].Value.ul = MSGSTATUS_RECTYPE_SMS; //is it OK to use this flag (designed

for SMS)? or is there a similiar flag for MMS?
props[2].ulPropTag = PR_MESSAGE_FLAGS;
props[2].Value.ul = MSGFLAG_FROMME | MSGFLAG_UNSENT;

//assign the property to the message
hr = pmsg->SetProps(sizeof(props) / sizeof(props[0]), (LPSPropValue)&props,
NULL);

//send the message
hr = pmsg->SubmitMessage(0);

The above code can send SMS successfully just by modifying pfldrDrafts to point to SMS message store and change propRecipient[1].Value.lpszW as commented. How to make the code send an MMS successfully?