Transfer fuel from trim tank

[b747]

Hi, how do i transfer fuel form trim/tail tank ? 

 

Thanks

[b747]

If I press on FWD on the T TANK switch nothing happens, same if i set the pump to ISOLATE or OPEN on the FEED Switch

 

Is this correctly modeled? The Fuel stays same quantity on T TANK nothing happens. If it is correctly modeled how can i make it work?

 

Many thanks