Queue and custom context

Hello.

How I can send a queue call to the member custom context?

If we create queue in custom config file, we can do this writing:
member=Local/number@custom context

But freepbx does not describe member this way.
How can I do this with freepbx?

You can not. FreePBX logs all members in as @from-queue. You would need to write your own dialplan to log agents in and out and use your dialplan with that feature code.