asterisk users - Nov 2007 - SPA-2100 into Paging System "Hangs"

We've got an SPA-2100 connected to * and then into a paging system on 
one of the FXS ports.  We are having an issue where the paging system 
doesn't hang up the line, so it stays offhook forever and obviously 
makes in unusable.  The paging company says that the SPA needs to hangup 
the line once the calling user hangs up the phone.  Any idea how to make 
it do this?  It doesn't do it by default and I don't see any settings 
that might help with that.  If I plug an analog phone in, it works just 
fine.

Peder