Set value to Symfony custom select_month_tag item

Question

I am using the select_month_tag and select_day_tag in a new Symfony 1.0 project (I know, out of date, but it's what we're using). In any case, when using the tag I know I can set the default first item in the select object to a custom item by using 'include_custom'=>'My Custom Value'. However, by default, Symfony does not give this first item a value. On top of this, I am using a JQuery LiveValidator that seems to require a value to check against for dropdown validation. Does anyone know if it is possible to assign a value to this first dropdown item in the select_month/day_tag(s)? (OR has anyone used LiveValidator and know of a method to validate if an item with NO value is selected?) Thanks in advance for any help!