Did you ever loosen the cam sprocket bolt first? If not you need to break it loose, then with you cam lock tool still in place, confirm that the cam sprocket can spin freely, if it doesn't tap the back side of the sprocket with a chisel/punch to pop it loose. The cam sprocket bolt stays loose until the belt it put back on and tensioned.
What you need to do is the following: (and you don't even really need to do all this until you are ready to put the new belt on and time the pump)
1. Have the cam sprocket loose, have your cam lock tool in place when you #1 is at TDC, sounds like you already did this, shim the cam lock tool evenly if needed. I have never shimmed one, and have always has good luck on the timing.
2. Install your new belt (don't tension yet), reinstall your crank pulley and bottom cover.
3. Make sure you IP lock pin is in.
4. Rotate the motor/flywheel back to the TDC mark.
5. Now you have cam at TDC, flywheel/motor at TDC, IP at TDC.
6. Tension the new belt to spec. Tighten the cam sprocket (having the cam sprocket loose while tightening the belt allows the belt to be tensioned and any torque or rotation that wants to be transmitted into moving the motor while tensioning the belt will simply be transmitted into spinning the loose cam spocket, which doesn't matter because the cam lock tool is keeping the cam at #1 TDC )
7. Check to see if flywheel is still at TDC, it should be, if it isn't you did something wrong.
8. Remove cam lock tool and pump lock pin, then i usually rotate the motor one or two full revolutions, and back to TDC on the flywheel, check to see if you can still install your cam lock tool easily and the IP lock pin slides in, if it does you are good to go, if not something moved and you have to start the process over.
9. If you are good, now you can rotate back to TDC on the flywheel and start the IP timing procedure, which is another subject. Discussion of timing the pump can be found here.
If this is the first time for you timing a pump it might take an hour or more, after doing it a handful of times myself, i can do it in about 30mins now, not all that tough just follow the write-up or the directions in the bentley manual.
http://vincewaldon.com/index.php?option=com_content&task=view&id=24&Itemid=28