Yes it is possible usually all you need to do is create a voice user with a forward. I would start by checking with the provider and seeing if they rejected the call for any reason, make sure you have a fresh current call example when you call them. If they never see the call you will need to provide a copy of your config with usernames and passwords changed, and the following debugs:
debug voice switchboard
debug sip stack messages
debug voice verbose
Some providers require extra steps for call forwarding since call forwarding makes the original inbound caller id the outbound caller id, some providers only allow outbound calls from numbers on their system. Sometimes you can fix this by using a DNIS ANI Substitution and that will work, sometimes you may have to add P-Asserted Identity depending on the provider requirements. Usually the provider will give you the requirements for doing call forwarding, then depending on their requirements will depend on what exactly you need to change.
John Wable
