Hi Todd!
Thank you for the reply, I wish it would be so easy....

When I go to the iSCSI initiator, on the portals page I read "Please disconnect from Target first". When I go to the target manager, I read "Volume Group exist, connection to target can not be interrupted". So there is no chance for me to remove the iSCSI connection without removing LV and VG?!?! Or am I wrong...