You can get the case_id so that you can use it as parameter to workflow::case::role::get_assignees in addition to role_id.
Check the code in bug-tracker/www/bug.tcl then just use your values for bug_id
set case_id [workflow::case::get_id -object_id $bug(bug_id) -workflow_short_name [bug_tracker::bug::workflow_short_name]]
Problem solved. I ended up creating an API ad_proc bug_tracker::get_items
the main part of it is:
set role_id [workflow::role::get_id -short_name $role -workflow_id $workflow_id]
set user_id [lindex [lindex [workflow::case::role::get_assignees -case_id $case_id -role_id $role_id] 0] 3]
the rest, i followed your tips above in this thread to get the parameters here and there
Thanks a lot!