Is there a way to return the Basecamp URL of a Fogbugz case via the Fogbugz API?

I am trying to query all Fogbugz cases that contain Basecamp URL's, in order to match these against open Basecamp projects/to-do URL's.

The problem is that the Fogbugz API has no mention of the Basecamp Project URL in it's documentation. I can return a list of cases that contain Basecamp URL's, but I cannot开发者_运维知识库 get to the actual URL's.

$search = file_get_contents(FBZ_URL.
    "?cmd=search&token=".
    $token.
    "&q=Basecamp+Project+URL&cols=ixBug,sTicket,sTitle,tags,dtDue");

Is there a way to do this?