Field Validation on Form Save

Hi,

We need to validate the form inputs when user tries to save the Offline Form.

Like, If a field is mandatory and user hasnt filled the same, he/she should not be allowed to proceed with Saving of the form.

I tried with PreSave and Form.execValidate method, but couldnt find any handle over the Adobe Readers Save button.

Any hints, suggestions would be really helpful.

thanks,

Mausam