IEnumerable as parameter is generated as VT_UNKOWN

[marklechtermann]

In case of IEnumerable (this interface is ComVisible=true in System.Private.CoreLib) dscom should generate:

type: VT_PTR -> VT_USERDEFINED refType: name: IEnumerable

As example:
void MyMethod(IEnumerable elements);

[marklechtermann]

System.Collection.IEnumerable is an interface from System.Private.CoreLib.
A type library for System.Private.CoreLib is not provided from Microsoft.