How to enable users to sign and return fillable forms

Hi,

     I have completed a fillable form with a signature box (this is a registration form) to send to users. I have had responses that say (depending on extended rights) that the form can be completed and saved but not signed or signed and completed but not saved.

is there any way to have the form completed, signed and returned.

Apologies if I am missing something really obvious.

thanks

(should mention that i was going to use the convert to Echosign function but some of the fields have javascript which is not sopported after the conversion).