IIS6 web application security exception

On IIS6 on w2k3, I have a problem with a specific web appliation. The
application in question is Outlook Mobile Access for Exchange 2003
(/oma).

When accessing the virtual directory, I get the following error:
Security Exception
Description: The application attempted to perform an operation not
allowed by the security policy. To grant this application the required
permission please contact your system administrator or change the
application's trust level in the configuration file.

Exception Details: System.Security.SecurityException: Request for the
permission of type System.Security.Permissions.RegistryPermission,
mscorlib, Version=1.0.5000.0, Culture=neutral,
PublicKeyToken=b77a5c561934e089 failed.

How do I change the trust level, or is there another solution?

Best regards, Rasmus

Rasmus,

Since this problem is directly related to configuring IIS for the purpose
of getting OMA to work, this question would be best answered on an Exchange
2003 discussion group. This group is primarily monitored by people that are
experienced with IIS and not necessarily the various applications that
people use on top of it.

Thanks,
Brian Murphy-Booth