Zkus tohle, našel jsem na to netu, prý to funguje.

1. Put Trevor on top of the strip club, right above the H marker, on top of a ventilation. (You reach the roof by climbing the ladder in the back alley.)
2. Switch to another character (preferably away from the strip club), then switch again to Trevor. Trevor should "fall" through the roof and spawn into the club. You will notice that the H marker has disappeared, and the mission can not be triggered from inside.
3. Walk into Trevor's office near the back door (the door can be opened, but don't go out), and switch again to another character (Franklin or Michael).
4. Quick-save your game (on a new slot, just in case). Reload your game via the menu.
5. The H marker should have reappeared. With your current character (Franklin or Michael), drive to the club and get close to the back door.
6. Switch to Trevor, who is still inside the office; it should automatically trigger the mission.