How create Solid Filled Region?

Hello!

I try create Filled Region with pattern type Solid Black.

I use next code:

            Dim fillRegionTypes As FilteredElementCollector = New FilteredElementCollector(doc).OfClass(GetType(FilledRegionType))

            Dim myPatterns As IEnumerable(Of FilledRegionType) = From pattern In fillRegionTypes.Cast(Of FilledRegionType)() Where pattern.FamilyName.Equals("Filled region") Select pattern

But in some rvt files it's not work.

How  create Solid  Filled Region?