simple wash water tank question

[shogun]

When I bought my Highline it had no wash water tank, probably broken and removed by P/O.
Now I got a used one. There is on the 750 a steel heat shield between tank and engine. This is popped into 3 plastic holders which onto the tank.
Looks like these vacuum suction taps/caps but they are actually inserted in a kind of plastic ring on the tank.
2 of these are slipped out from the tank 'ring'.
How to insert them again? Just pushing it it or heating up in hot water? Am a bit afraid that the plastic will break. Paid on the net for that used thing abt. 80 $ plus postage, incl. 2 pumps.
Sorry for the not so detailed explanation but I assume you know what I mean ;)
That is how it should be attached.
http://img113.auctions.yahoo.co.jp/users/1/4/1/4/sato4817-img600x450-1113812089dscf1168.jpg

The explosion view
http://www.bmwtoolkit.com/BMW/61/0004.png

[Paul in NZ]

They look like those "washers" that have say three tabs on the id which grip the short plastic stud on the tank.I Dont know if there is a tool to put them on and take them off....ie they come with the tabs pointing up or down and you "flatten" them to make the tabs grip the plastic.....

[shogun]

Paul,
I know how to remove the # 10 washers. I mean on the back side of the heat shield plate, there is something made of plastic which is either glued or 'plastic welded' onto the tank.
So the problem is the attachment of the 'base' of the plastic which is attached to the washer tank where the screw is in a round shape piece of plastic. The drwaing for the part s catalog is not 100% correct.
Looks similar to these plastic cups for attaching the solar panel to the front window. But it is solids plastic. Assume it broke off.
http://i23.ebayimg.com/02/i/02/02/cc/ea_1_b.JPG