C# application compatibility problem

Hi  ,

I have writed an C# application with these informations:

Language: C# 4.0
Target Framework: 3.5
Platform: x86

Now I need to convert this application to mono develop but unfortunately mono develop need to work with framemork 4.0 for optional parameter support.

I try to find a solution, but probably the only way to follow is change the target framework to 4.0.

I have changed the target framework to 4.0.

I run my application and now don't find the registry keys.

I have investigate about it and seem with framework 4.0 the class:

//
Microsoft.Win32.RegistryKey
//

work in different mode.

I was try to access with my key:

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall\Pro Data Dentista

but there is no way to access because return always null.

In my framework 3.5 copy the application access without problem to all keys.

frankly I don't want change the target from 3.5 to 4.0 but probably this is the only way to solve problem and I don't known what type of suprises I will see after.

In this moment the registry access don't work with framework 4.0.

How I can solve ???

Thanks you !!