Never mind.... got it updated through another way....
Yesterday I have ordered an extra server, but that server doesn't seem to have a ESXi 5.5 template (only 5.0), while my other (Cheaper) sys-machine DOES have 5.5.....
Please help me out to have the 5.5 template on the other server as well!
The server ID with 5.5 is 96015 and the one that doesn't show the 5.5 template is 328710.