How to send MMS with pc via cellphone to Wap Gateway or MMSC?

Hi,

is there anybody who can me explain how to send an MMS via PC
connected to a cellphone with e.g a serial datacable.

What I know about sending stuff with pc via mobile:
I know how to send SMS, Picture SMS or EMS with a PDU which is send
form the pc with a at-command over a terminal program or from a
software to the cellphone. The cellphone takes over the transmission
of the SMS.

What I know about MMS:
I know that a MMS consists of its content which is represnted in SMIL
and a header which contains several information about the delivery. I
have heard that the a MMS is send by Wap Push but I don't know how to
realize this over pc.

My question is how can I get a connection to the WAP gateway or the
MMSC with my cellphone over pc so I can send an MMS from out a
software.

Or can s.o. explain me the general delivery of MMS via PC with the
help of a connected cellphone.

Thanks !!

Turrican