Hi there

I don't have any links handy - but a few points:
1) If you enable IDR - you can always fall back on manual DR from the same backup set - so you might as well use it even if you end up using a manual process when doing restores - Note in the current versions of BEWS, IDR is part of the core license when older versions had an extra cost associated with its use.
2) There have been some combinations of hardware that IDR does not handle very well - in those instances either plan for a manual DR or perhaps investigate what BESR can offer (BESR is a Block level imaging product, BEWS is a file level backup product)
3) If you ever have a real disaster (instead of a test scenario) and IDR does not work, then I would suggest switching to a manual DR as being the most efficient way to recover - as unless Symantec Tech Support have seen you exact problem before, the troubleshooting process might be longer than the manual DR process.

For info a Manual DR is install the OS followed by enough Backup Exec components to allow a restore to be run.