[Interest] Latest on Mac App Store + sandboxing?

[Paul Miller]

As the Sandbox deadline is now March 1, today I tried to submit an 
update to one of my Mac App Store apps and received an email with this 
information:

"Invalid Signature - the executable 
<application>.app/Contents/Frameworks/QtCore.framework/Versions/4/QtCore 
is not signed, the signature is invalid, or it is not signed with an 
Apple submission certificate. Refer to the Code Signing and Application 
Sandboxing Guide for more information.

Invalid Signature - the executable 
<application>.app/Contents/Frameworks/QtGui.framework/Versions/4/QtGui 
is not signed, the signature is invalid, or it is not signed with an 
Apple submission certificate. Refer to the Code Signing and Application 
Sandboxing Guide for more information."

I am using Qt 4.7 frameworks I built myself.

This didn't happen before, so I'm wondering if this is some other aspect 
of the sandboxing rule that is newer or if maybe I just need to do 
something special to get them signed.

I came across https://bugreports.qt-project.org/browse/QTBUG-21609 which 
has a bunch of information but still seems unresolved.

Can someone summarize what it takes to get a Qt-based application 
submitted properly to the Mac App store these days? Is it even possible? 
Since the sandbox deadline isn't for 3 weeks, is there something else I 
can do instead?