I don't use Whatsup, but seeing how another app is going the "non-native UI" way, please have a look at these two apps:

• Friends
• Quickddit

Both have many more options than is needed for Whatsup, yet they both have an elegant and native solution.

On a related note, I know of two apps that had gone the same way as Whatsup (Sailimgur and the IRC client) and both are pretty much unusable for myself (not even talking about the aesthetics) and it is also absolutely unnecessary in both cases. If I didn't mind apps with non-standard UI controls, I wouldn't see why I couldn't choose an Android app in the first place.

It's just my opinion. I hope that more developers will look into native ways while searching for the solution to the 'too many options' problem. The combination of pulley menus and most importantly attached pages is crucial.