SDU Format.

Hello All

i have written a simple udpclient prgm which will send 
S_Unit_MethodInvoke to wap gateway. Method pdu is put in to the 
buffer,thus buffer contains wsp pdu. is this correct???.

But when wap gateway recieves it's throwing up warning 
"unsupported token or header".

In the wsp spec i had read that wtp sdu contains wsp pdu. so what 
this wtp sdu means,is it service primitives??.
which contains specific paramters for particular service 
primitives.  please guide me. are there any spec which mentions 
the sdu format.

regards
Nigar