How to add a rule for transfer a call to a trunk gateway?

I have a request to make a call via trunk gateway. But I don’t know how to configure the extension? Please help me!

Now, this trunk gateway need me send authentication information without password, and its port is changed to 5068. How do I configure?

For example, I add a new extension like this:

exten ==> _002.,1,Dial(SIP/87734567@${EXTEN}@,tT)

Is this right?

Nobody knows? Please help!