No output voice sip hardphone -> * -> sip.voipcheap.co

Hello.

I’m having troubles making calls using my sip hardware thomson 2030, asterisk server and sip.voipcheap.com sip account. I hear people speaking but people can not hear me. Everything else works perfect:
intranet sip soft -> TDM400 landphones
intranet sip hard -> TDM400 landphones
intranet sip soft -> sip.voipcheap.com landphones
outside landphone provider -> TDM400 asterisk board -> sip.voipcheap landphone (asterisk forwarding from TDM400 incomming call to sip.voipcheap.com landphone)

The error is just using sip hardphone.

This is my network schema: http://www.lefatech.com/network.gif
This is my router NAT configuration: http://www.lefatech.com/nat.gif

Any idea?

Regards.

any idea on this issue? Maybe some way to configure my thomson