Can't view my Registered .NET Assembly in NAV2009 R2

I’m trying to experiment a bit with the .NET Assembly in NAV2009 R2,

So I did register a third party .NET Assembly with the syntax below,
using CMD.EXE launched as Administrator :

C:\Windows\Microsoft.NET\Framework\v4.0.30319\regasm.exe C:\TEMP\Interop.MyEngine.dll /registered /codebase

C:"\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\Bin\NETFX 4.0 Tools\gacutil.exe" /if C:\TEMP\Interop.MyEngine.dll

The assembly registered properly from the command line,
however I can’t view it via NAV2009R2 when I declare
a DataType of DotNet and lookup the various assembly available …

I’ve got the frameworks.NET 4.0 installed on my machine, and the component support it.

What else should I be checking ?