Changing Comment Backcolor w/VBA

Does anyone know the correct syntax for changing the back color of a comment.
As I get older I can't tolerate light backgrounds and I've been manually changing the background of my comments to a dark color.
I'm looking all around and I see countless examples of how to change the text and text font but nothing that addresses the back color of the comment.
What I have below works fine on the text and the last line that is commented out is the last version I tried to change the back color.
It throws an object doesn't support the property or method error 438.

Sub test()

Dim cmt As Comment
Set cmt = ActiveCell.Comment

With cmt.Shape.TextFrame.Characters.Font
      .Name = "Tahoma"
      .Size = 13
      .Bold = True
      .ColorIndex = 0
End With

'cmt.Shape.TextFrame.BackColor = RGB(0, 0, 50)

End Sub

Something you can practice with.

cmt.Shape.Fill.ForeColor.SchemeColor = 15

Dave,
I couldn't find any documentation to tell me what numbers to use for certain colors so I used trial and error.
It seems like some of the colors come up under more than one number.
You saved me a ton of time, thanks very much for your help.

I found some good code related to formatting comment boxes for anyone interested.