Data is not being passed

Hi all,
I have tried to prepoulate data( The first and last name of the user)on to the form using the form render service. I am invoking the render service in the initial stage when user opens the form. So for the main input form in the advanced setting I am using calling the render service. The problme is the data(users first and last name) is getting populated but when I fill the form and pass it to the next stage there is no data on the form except for the next users first name and last name which is not desired.
I do not understand the reason why the data is not being copied to the next satge. In the assign task output variable i used the same variable as input...but nothing is being copied over.

Please help me out.

Thanks in advance!