Calling external aspx page and trigger its __doPostBack event automatically

Hello,

There is some public aspx web application that shows about 80,000 records in a datagrid, using paging functions. The datagrid shows about 50 records per page.

The thing is that we need to download the whole 80,000 records. Obviously, any guy could load the aspx page in a browser and, during two or three days, download the 80,000 records loading every datagrid page by mouse clicking.

We'd like to avoid that job, creating a program that has to:

- Load the aspx page (http://www.thatsite/apps/ds027/TheList.aspx)

- Call the javascript function __doPostBack(eventTarget, eventArgument) with these parameters:
  __doPostBack('ctl100$cphBodyMain$gvwInscripciones', 'Page$1')

  This function __doPostBack fill a page of the datagrid.

- Parameters in eventArgument will be 'Page$1', Page$2', 'Page$3', etc...

- Download the 50 records from every datagrid page that has been loaded until we complete the 80,000 records

Please, don't get us wrong. We are not trying to hack or attack anything. All we need is to download the 80,000 records that are showed in a public aspx web site.

Is our idea correct? Is it possible to make a program to do that?
If you guys could give us some directions about how to start or links of program examples... it would be great. Thanks a lot !
Thanks