RadioButtonList - Setting fixed width on columns?

I have a databound RadioButtonList that I want to split into 3 columns.
So...I set:
RepeatLayout - Table
RepeatColumns - 3
BUT the table columns generated doesn't have a fixed width so the space between columns varies depending on the length of the text in each column. That's really ugly!
Is there a way to set a fixed width on the columns generated by the RadioButtonList control?
Or do I have to generate my own table with RadioButton controls?
...