Transfer with T2XG and call back

[hercross]

Hi, I have several T2XG or P connected with Asterisk. For transfer I'm using TRANFER + EXT or directly press key from exp.

Now I need to use that when I transfer a call if the destination doesn't answer, the calls back to the original extension.

With Asterisk there are a feature code to use it, I use # + ext.

This code works If I press # + ext, but if a press # + key(blf in my exp), it doesn't works.

How can I use it? Or are there any other way to do that?

Thanks