Encryption step in actions grayed out in Acrobat 11

I like to password protect a dynamic PDF form (xfa) stored on a network drive with a Acrobat action. When I run the action, the action shows the encryption step grayed out (disabled). It works with flat PDF's but not with PDF Forms. (XFA)

In Acrobat Pro 10 the same action works without any problem.

Is there any help for this issue?