Puchasing app from the App Store?

I purchased an app (Adobe Photoshop Touch) for my iPad from the Apple App Store. It downloaded fine and it works perfectly fine but when I go to the App Store to view all my purchased apps (both in the "All" tab and the "not on this ipad" tab) it won't show up in the list! The reason why this is a problem for me is because I want to download Adobe photoshop touch on my iphone also without paying for it again using the same apple ID but now I can't because that app won't show up in the purchased apps list at all! When I search for it in the app store they ask me to pay for it again!

Why is this happening with that certain app? All the other apps show up in the Purchased Apps list except for Photoshop!

The app for ipad is different than in iphone. It might not compatible with iphone so they don't let you download it on iphone i think