Hi Carl, thanks for your response, in summary what we are trying to do is:

-Change the form's action so we can call the aspx file through the submit.

-Execute the aspx code, after that I'm trying to go back to that specific form, change its action (using its normal action Forms/form/submit) and activate an autosubmit, so we could continue our normal process. 

The problem is that, once we try to redirect from aspx to the form it doesn't work and our process doesn't finish.

Ah, if you're redirecting/navigating around Laserfiche Forms it's significantly more complicated as you'll need to manage session tokens generated upon time of request of the Forms business process in order for submit buttons to work.

I'll have to bow out as I've only been able to do an autosubmit on an unstarted Forms business process and the back peddling to change an action and submit, I've not been able to reverse engineer.

Here's a link to some detail regarding the autosubmission of an unstarted Forms process.

https://answers.laserfiche.com/questions/77330/HOW-TO-Launch-a-Forms-Business-Process-via-Workflow