Want to place call from one asterisk to other asterisk server communicating via aix & dundi

I have two issue.
1:- I have two asterisk server running US and shrilanka, I have DID number which works fine for US extension but now i need to add it to the extension present in shrilanka asterisk server. So that any person from US call to DID number of my US asterisk server should get connected to extension present shrilanka asterisk server.

2:- I have IVR running on US asterisk it directly connect to US extension with out any issue , but i also need it to transfer the call to shrilanka extension.

My aix and dundi is working fine which means i can call to US number from shrilanka asterisk and vis versa.

So what have you done so far to get this working? You say you can dial from an extension in the US to an extension in Sri Lanka without problems (and vis versa) so the IAX trunk is working fine. What other steps have you taken and what happened?