Here a snip that send a sms from position 1, then wait for ok.

SerOut2 TX,TTMode,["AT+CMSS=1",Cr] ’invia sms presente in posizione 1
gosub Poll_Ok ’sms inviato ?


Search with google "allarme SMS per siemens e pic12f675"
You should found a my program that uses a siemens C35 and send the message stored in pos.1 from sim card. I do not know if it works with C55.
Regards
Gianni