I’m still having this stupid GAC-related problem!!!
Anyways I think I found yet another useful resource to my GAC collection.
It seems that apart from going to the effort of adding the assembliy to the GAC you also have to add it to the web.config, like so:
<add assembly="MerrillLynch.Bank.Framework.Web, version=1.1.2005.0, publicKeyToken=80a6f6408bd93158, culture=neutral" />