I moved to IDM 4.5.6 and am working with designer 4.6.1 now. I have a couple of workflows with an @ character in the target expression of a data item mapping of an activity.
I can't deploy my workflows anymore. The project checker gives the following Error:

Severity: Error
Description: Invalid expression for 'Data Item Mapping/Target Expression' in activity 'Activity': flowdata.map/initiator/@email
Details: Expression: flowdata.map/initiator/@email
Error(s): Error: at line 1 and column: 24. XML runtime not available

What is going wrong here?