Using \#\ to pass mulitiple values to a multivalue parameter in SSRS 2012

I'm using a graph to pass multiple values to a drill through report.  

Under the series properties,  action options, I'm passing multiple values to another report's parameter.

In SSRS 2005 I used to be able to do this passing in this format:

"ValueA\#\ValueB"

In SSRS 2012 this does not work.  Is there a new delimiter, or is this simply not supported anymore?

Now when I try to drill through on the graph, it is not populating the parameter at all.