I currently have a small side project with SocialSecurityValidator, and we are stripping all of the dashes out of the format, and when we passed in just a number to the validator, it screamed bloody murder, because it couldnt use a string function charAt().

so I simply passed the number in with a .toString()
as
//mySSN is a number
ssnV.validate(mySSN.toString() );

mxml:
<mx:SocialSecurityValidator
id = "ssnV"
/>