Andreas,
There aren't many customer-facing examples in .NET for dealing with SAS metadata, I'm afraid.
However, SAS EG and SAS Add-In for Microsoft Office are .NET applications, as you might know, so you should feel confident that .NET access to metadata is a well-supported mechanism.
The components to use are SASObjectManager (to connect) and definitions from the OMI.tlb (type library) -- all of the access to metadata and SAS workspaces is via COM interop.
The StoredProcessService.chm file in the SAS\SharedFiles\IntegrationTechnologies folder has some partial examples particular to stored process discover/running. You might be able to glean something from that.
Chris