Date Format for textbox in userform

Hi

I have a userform and in a textbox I want the date to be shown in this format SEP 2011, textbox is populated by a cell in an excel worksheet.

TextBox8.Text = Format(TextBox8.Text, "MMM yyyy")

I am using the above to format it it but it shows Sep 2011, how can I get the letters in capitols??

Thanks in advance