|If what you mean by "it will store and use later" as being able to recall prior entries (user names and passwords), it's possible, but it requires a seperate file.|
The command for setting from a file is:
SET /p Variable= <FileName.txt
Remember to change "Variable" and "FileName" to what ever applies to you.
Hope I've helped!
One last thing, I wrote a perfectly working log in/registration batch file for someone the other day. If you would like it, for reference or to use, PM me.