is there a way to make att_xfr app to hunt for dialplan without using loopback ?

intended use is...

<action application="att_xfer" data="2137 XML my_context"/>

which doesn't work

<action application="att_xfer" data="loopback/2137/my_context"/>

does work but.., i heard that "loopback is evil" and you shouldn't be using it

Thanks