Using "Cards" style in URCap installation is bad design?

The Style Guide states that you “Don’t use a Card inside of another Card”. I agree that this would be bad design. However I find it hard to adhere to this rule. The reason is that when overriding the buildUI() method, I cannot get rid of the default insets of the JPanel object that is provided as a parameter.
So since the URCap installation panel itself is a Card, then even the “outermost” Card that I design in my installation view will indeed become a Card within another Card.

Trying this in the buildUI() method:

jPanel.setBorder(BorderFactory.createEmptyBorder(0,0,0,0));

throws

com.ur.swing.AuthorizationException: Method not supported from URCaps

Has anyone gotten around this?