Diggit Drupalextras

Greeting to all
I am working with drupal webform. my site having 50 forms and have added validations also. i have 2 scenarios, one user will navigate to proper form and submit the values, the other one is webform data will come from xml file. i have requirement to provide the form in html form as well. And those html form data can be saved in xml format. so i need to provide an option to upload the xml file and store it into webform data tables. i know how to do this with feed api and/or through my custom module. But i don't want to insert directly to tables, instead data should go like web form submit click. In details, parse the xml data and do the server side validation as it is with webform submit button and save using the webform submission handler. So pls anybody help me how to achieve this functionality. And one more query can drupal have option to validate webform with xsd file.if there i can provide the validation in both scenarios.
Thanks in advance