Getting Variable Info from GUI to Custom Context

Okay, here goes.

In extensions_custom.conf I have a context that builds a data file on the fly each time a call is made to a certain phone number that is routed to an extension created via the FreePBX GUI.

The custom context has an extension of **333. Through the GUI I have a virtual extension that is 13332 that has a ring time of 1 and then calls the Miscellaneous Destination that dials **333 via the No Answer setting.

If I dial the GUI 13332 extension directly, I see 13332 as the {CALLERID(dnid)} in the custom context. If I dial the external phone number that is “connected/routed” to that GUI 13332 extension, then I do not get any information via the {CALLERID(dnid)} variable.

Having worked with Cisco IPCC for some time, they have a variable called OriginalCalledNumber which would show/pass the 13332.

Is there something similar in FreePBX/Asterisk or is there a way to pass that GUI extension information to the custom context?

I have tried several of the other Asterisk variables but none of them seem to pass that GUI extension information on to the custom context.
Hope I have explained this well enough. Thank You.