Sikkerhed og ASP.NET. trustLevel

Hejsa.

Jeg har en halvsvær nød at knække angående sikkerheden i ASP.NET. Det er på engelsk da jeg også har spurgt i en nyhedsgruppe: (microsoft.public.dotnet.framework.aspnet.security):

In an environment with a IIS shared by many users, I've decreased the
trustlevel on a site basis to trust level medium (in machine.config file). This restricts the web app not to have access to system event logs and file io access
outside their web directory etc. But, unfurtunately, there is a rather discouraging side effect - for some reason: When an external assembly is referenced from the web app, with it's DLL residing in the bin directory, containing for instance new web controls, the
load of these fails with an:

LOG: Policy not being applied to reference at this time (private, custom,
partial, or location-based assembly bind).
LOG: Post-policy reference: [Assembly Name]

If I drop the restriction, there are no problems. How can I solve this
issue?

Kan I knække den?

Mvh,
  Per