Just some sites, may help:
http://www.philsaeronauticalstuff.com/a-26b/a-26b.html
A link to a training video of how to fly an Invader:
http://www.zenoswarbirdvideos.com/A-26.html (haven't watched it, I refuse to install RealPlayer on my computer. One would assume that it'd have a few shots of the cocpit since it's a training video.)
You can probably use the contact info at the bottom of this page to request a photo of what you need:
http://www.historicalaircraftsquadron.com/phase.htm
Hope some of this helps.