Accessing an Indexed property - Two indexers?

Here's a C# line I want to duplicate in Progress.

Style s = diagram.LaneGrid[null, null].Style;

I can't seem to make this work. The progress docs seem to state that this is not possible (quote from doc below)

Am I stuck? I imagine I could write a quick C# assembly to help with this but I'd rather stay in pure Progress. Is there any way to do this?

Thanks,

Tom

Note:

.NET documentation strongly recommends that any indexed property should

only be created with one key for the indexer, and this is how all indexed

properties are defined for the Microsoft .NET Framework. However, it is

possible that other third-party .NET classes could define indexed properties

with two or more keys for the indexer, in which case you cannot access those

indexed properties in ABL.