the ability to use the CID of the Prospect is already in VICIdial in the campaign definition (in detail view: 3-Way Call Outbound CallerID)
also: what language are you looking for? do you want access to the parked call's CID in asterisk dialplan language, agi, perl?
much of it is in the channel variables, but you will likely need to also get information from the live tables in mysql to "cross-reference" and find the rest of it. (if you don't want to use the campaign setting)
PS: Thanks for posting you entire spec line
