Retrieve userid instead of lastposter from '_thread' table...

[tschai]

Hi all,

In the forum mainpage the lastposter ($lastposter) is been retrieved from the '_thread' table via 'member.php'
I want to show the avatar via the userid on this forumpage.

My question is:
-How could I possibly retrieve the userid via 'member.php'/'_thread' table of the lastposter (in order to show the accompanying avatar)?

or maybe easier

-How and where could I insert also the userid of the lastposter in the '_thread' table (in order the retrieve it dierctly later on)?

Any suggestions are welcome.

Thanks in advance.