I have not done this, but you might be able to set it in the Javascript in the doAuthen() function in $WEBDIR/lawson/portal/logon.htm.

document.body.style.cursor = "wait"; // turn on hourglass

document.body.style.cursor = "default"; // turn off hourglass

I couldn't get this code to work. I was told it had something to do with the login button passing control to another program or something like that. I put the code in every possible place but never managed to get it right.