Blocked Senders - Programmatic Access

We need to programmatically update the blocked senders for our exchange users
at the individual user level. We found an article showing where they are
stored in the registry. Our question is whether they are maintained
elsewhere in an exchange or outlook store, and if so whether there is a .NET
class/method we can use to access and update them? The blocked senders (or
safe senders, etc) wouldnt seem to fit into the usual "item" model.

We will be using VSTO SE, and when we posted to the VSTO newsgroup they
"recommended" we post here first.

Any help would be greatly appreciated.