With how you described it you should be able to change the tab shown by setting AFF_CONTROL_VESSEL to either VESSEL SPECIFIC or PORTCALLS or TECHNICAL STOP
Thanks Charley for your answer. I think it should work as well but it doesn't.
Actually i've found a solution for my issue and it works now.
I've created a editbox control in each tab of the data card with the "AFF_CONTROL_VESSEL" in it. Then i've used the control logic to hide it and now it works. When I remove the editbox, it doesn't work. Weird....maybe an EPDM bug...