Access Foreign Key Value from inside Mapping Editor script

Question

Hello, 
 
 Can anybody tell me how I can access foreign key properties from inside mapping editor inside database connector (scripting c#)? 
 
 Please see screen. 
 
 I have access to $UID_Department$ and now I would like to create the object to get the CustomProperty09 from it. 
 I already tried three different things (see first two commented out from screen) and also like this: 
 $FK(UID_Department).CustomProperty09$ 
 Every time I get a different error message. 
 Can anybody provide me an answer for this?

Markus Weiss-Ehlers · Accepted Answer

You do not need a script property to access values from foreign key references. Just a virtual property of type "Key resolution by reference". 
 See the following post as well: 
 There also posts that talk about scripted property like this one here