asterisk users - Jul 2005 - How to set the SMSC sender = VoIP provider 10-digit #

I have a VoIP provider that terminates to a PSTN 10-digit number.  I  
want to be able to send/receive SMS messages that appear to be from  
the 10-digit number that my VoIP provider gives me.

I am currently integrating Asterisk with Kannel and it works great.   
Unfortunately, my mobile phone provider Cingular, doesn't allow me to  
alter my number when I send out SMS messages.  Or at least I haven't  
gotten it working.

I am looking for an *affordable* solution that will give me access to  
the carrier network and allow me to set my SMS number so it matches  
the VoIP PSTN terminated one.  Does anyone have any suggestions for  
me?  Hope this gives you enough information.  I recognize the term  
affordable is rather subjective.

Regards,
HJ