Can I write a DynProperties in Runtime?

Can I write a DynProperties in Runtime?
I want to do this:

VBA Code:

thisProject.Passwords.ItemUser(p).DynProperties("UserGroupsImExpo") = myValue

It seems works but when the user is logged the UserGroup isn't change.
What I can do?

This is a migrated post! Originally posted on 09.12.2011 by user fransiska. Please be aware that information can be outdated.