databind format social security number

I cannot find anything on how to format a social security number in the
databinding property of a text box. Everything in the drop down is
preformatted like {0:D} or {0:C}. I cannot find any examples. I just want to
take a 9 digit number and put the hyphens in.

I have this: 987654321 and want to show this: 987-65-4321 using the
Bind("SSN", ?????????) property.

Here's one thing I tried but it didn't work:

<%# Bind(&quot;SSN&quot;, &quot;{0:'###-##-####'}&quot;) %>

I'd appreciate someone showing me exactly what I need to use instead of the
above to make this work.

Keith