If you need that, so you can later simulate keyboard shortcut to call the plane, you can easily call it like this:
ModelDoc2 swDoc = ((ModelDoc2)(swApp.ActiveDoc));
swDoc.Extension.SelectByID2("Top Plane", "PLANE", 0, 0, 0, false, 0, null, 0);
where swApp is your current SldWorks.SldWorks instance.
You can change "Top" in the first way to any Plane you need. In the second you have to find the right ID for your plane, look in your API help in SolidWorks.Interop.swcommands.swCommands_e.
Sorry if writing in C# isn't good for you, but I hope that helps.