Re. maintenance of the A330 MRTT; my understanding is that if the a/c and operator are certified to civil ETOPS standards, then any maintenance on the a/c must be performed by ETOPS-qualified personnel to the appropriate JAA quality standards... The full requirements as published by the CAA can be viewed at
http://www.caa.co.uk/docs/33/CAP513.pdf
Bodge tape and blacksmithery would not be acceptable.