Field "created by" when using word template with different user from the same computer ?

Hi,

I'm facing an issue when people save a word document into a document library with a different account than the currented user logged on the computer. 

For exemple someone call "A" open a windows 7 session and starts sharepoint.

He goes into a  document library and use a word template from there to fill a document and save it into the sharepoint library. 
Someone call "B" comes and change from the sharepoint the user and get connected has "B" into Sharepoint.
When "B" use the word template from the library and save into this library, the column "created by" is filled in with the current user logged in Windows 7.

am I the only person having this problem ? 
Does anyone has a solution ? 

Thanks for helping.

Regards