How to "add" additional informations to existing records using import?

Hi,

I have been trying to figure out how to use the "Data Import" to add info to 5 fields to existing records (Products database). I found this guide:

http://www.crmsoftwareblog.com/2010/05/using-the-import-tool-in-microsoft-dynamics-crm-to-update-existing-records/

As far as I understand I cannot import the new informations (Mapped to an existing field in CRM). I have to export the current data, and import it again with the new informations?

So I tried exporting the existing informations selecting "Export To Excel". I cannot select the first option "Static worksheet with records from this page". Since I have 50.000+ records. So my only option is to select "Static worksheet with records from all pages in the current view", and then "Make this data available for re-importing by including required column heading".

After I have done that there is only 10.000 rows exported, instead of 50.000?

Further more I find exporting and reimporting not the ideal solution, is there any other method of doing this "Manual"? (I do not wan't to use any integration services at this point)