If it helps anyone help me faster (grin), I located when I believe the now-missing "adventure_id" was first introduced. Browsing through Sourceforge, version 1.16 of eq_packet_structs.h, you can see it stuck in around /* 6028 */.
http://eqemulator.cvs.sourceforge.ne...16&view=markup
I think this means this used to work, but has since been lost. Any help would be appreciated finding this location again, or a hint how to figure it out myself.