Well, I figured it out myself and since I did not receive an answer from anyone, I will answer the question for others future reference.

The pump has 6 bolts, 3 hold the pump together and 3 go thru into the cam cover. Look at the blanking plate in front of the other cam to determine which are thru bolts.

And also importantly, there is no need to remove the pump to change the thermostat on a 280TE. There is just the barest clearance between the thermostat housing & the pump and it is (in MB fashion) just enough room to do the job without removing the pump.