asterisk users - Mar 2006 - Budgetone strange problem - have to press hold on and off to connect call.

I have a strange problem in that I have put a budgetone out on the internet that
connects to my * server that's behind a firewall.
They can call me I can call them  and it works fine. However, I have setup a
link to sipdiscount on my * server. If the budgetone user  calls  via my * box
to sipdiscount all the budgetone user hears is silence and the called person
hears silence as well when they pick up the phone. If the budgetone user then
hits the hold button then the called party hears the music on hold and then when
the budgetone users takes it off hold then they can start talking to each other!

The phone has  firmware 1.08.16 same problem with reinvite yes or no.

Any ideas?


Chris