This "environment variable" thing is kinda tricky ... the thing is ... in which "user context" should the variables get resolved ... the callers or the called ?

For example if using %USERPROFILE% - should it use the caller's (users) %userprofile% or should it use the %userprofile% of the userid your running it under. Dynamic environments variables that have been SET up-front, can only be resolved in the CALLERS context.