Virtual property for behavior


I'm trying to add a virtual property to ADSAccount (user) to get the TSBBehavior ITDataUsage of an ADSAccount, with the intention of using the value in mapping conditions to control the rogue modification correction.

I have added an Object Reference 'vrtManageLevel' with the Route UID_TSBBehavior.ITDataUsage.  This makes the UID_TSBBehavior light up yellow as expected.  

If I look in the OneIM target system browser the vrtManageLevel has no value.

I have also tried adding a mapping for the virtual property to ExtensionAttribue1 to see if it has a value, but no value is written to AD when changing the ADSAccount.UID_TSBBehavior which causes an AdHocProjection 

Is what I am trying to possible? Am I testing incorrectly?

Thanks for your help!