Fill up Acrobat Reader form automatically

Hello

I tried to search forums, but with no success. So I ask you.

My goal is with another program automatically open an existing pdf-document (form) using Acrobat Reader 6.0 and fill up the form. User then can print it out, no saving is needed.

For example, a file like this (file will be located on hard drive, not in Internet):
http://veeb.haigekassa.ee/files/est_blanketid/kindl_nimekiri.pdf

So I need to
1) open an existing pdf-document using Acrobat Reader (6.0).
2) automatically recognize editable fields
3) automatically fill these fields without user intervention
Then user can check the data and print it out.

My question is:
Is it possible to do using Adobe standard API-s or dll-s?
I couldn't find any :(

I found a third party software which should do that (iTextSharp)
http://www.c-sharpcorner.com/UploadFile/scottlysle/PdfGenerator_CS06162007023347AM/PdfGenerator_CS.aspx
but I would like to do it without using third-party software.

Thanks,
Urr