Lars,
Now you know why I have been harping for upgrade scripts (which BTW aren't happening for most packages). For OpenACS to succed there needs to be a path to get to the next version. Telling someone to reload from scratch is a shit solution and prevents momentum.
I wish I had an easy hack for you but as you found out the object model (and its complete misuse) really gets in the way of a dump into a new system. Upgrade scripts for all the data-model changes would go a LONG way towards making this usable.
I would hope that the Gatekeepers don't let 4.6 out without EVERY package having upgrade scripts, with NO EXCEPTIONS. In fact I think that one of the testing procedures should be in place upgrade.