Things to watch out for when opening / closing the Electronic handbrake on VW :
Do not perform any of the Basic Settings while the brakes are disassembled!
Opening, closing, function tests, and otherwise cycling the Electronic Parking brakes should only be done with the pads and calipers properly installed.
Definitely do not take the pads out before opening the calipers!
When opening or closing the calipers wait 30 seconds after the brakes stop moving before carrying out the next step.
Due to a firmware problem in some modules, failure to wait can result in damage to the control module.
Step by step instructions for all GEN2/3 versions plus A8 which has a slightly different procedure in the Technical documentation section.
Another top tip
once you start the procedure , finish the job ,do not have lunch.
the calipers "creep out" over time and this can cause problems.
Also as in the instructions make sure the batery is fully charged.