You could try using a company 2sms.com (they have a smsc link) which has lots of ways of getting SMS into their system. I post xml from a php script that processes messages that arrive to kannel. Depends how reliable u need the message delivery to be. I used clickatell for a few days, found them totally unreliable.
Anyone got sms message queuing to work with the siemens tc35 yet? G.