Excel import functionality in AX 2009

Hello,

I would like to know if the Excel Import functionality in AX 2009 can be used to modify the existing system records. As of now I am aware that the system only allows the User to create new data using the Import from Excel functionlaity.

I would like to know if there is some set up in AX 2009 by which the same Import from Excel can be used to update existing Records in AX.