UWL people search results

Dear colleagues,

if Im creating a new task in a room-UWL (EP 7.3 SP6) and use the people picker to find a person to assign the task to, Im missing the most of available UME users in the results. I thought I should be able to find all of them, something must be wrong. I tool a look to UWL FAQ but wasnt able to find any clues on this issue. Any ideas? Thank you,

regards