No access with SP Designer 2010 after change to FBA and Windows at the same time - Does this work with SP 2013

Hi All,
     It seems you can't use SharePoint Designer 2010 to open a site if you have both forms and Windows Auth selected.
Is there any way around this if i want to use the 2 at the same time?

How does this work with SharePoint 2013 as i would be doing some migrations?

Cheers in Advance