To Access A Shared Folder Providing User Name And Password

Hi,

My code should copy files from a shared folder.
the share can be accessed by all who can provide a specified username and password.

I use the following code:
But where to specify username name password to access that folder?


DECLARE @cmdstr varchar(1000)

set @cmdstr = 'copy \servernamefoldername$ C:DataExTest'

print @cmdstr

EXEC xp_cmdshell @cmdstr

Any sort of help would be highly appreciated.

Thanks in advance