mail sending function module not sending mails,req better FM(fast delivery)

Hai guys,

i tried using the FMS

SO_NEW_DOCUMENT_ATT_SEND_API1

SO_DOCUMENT_SEND_API1

for sending mails from ABAP program.

earlier they used to work fine.

but now i dont get mails,(very rarely once in 50 times i get mail).

however,when sheduled in back ground ,I get mails ..(are these only meant for APlication server)

now,i need a better FM

i dont remember the name ,but thers a CLASS or FM(i think for sendign EXCEL attachment)

which was very FAST.

pls help me get a better way..