NetWeaver 04 - SP11, Java OS User Passwords unknown

Hi all, question for you guys out there. As many, I am trying to install the Sneak Preview SAP NetWeaver 2004 SP11. However when I start the install, I need to identify the location of the sdk (c:/j2sdk1.4.2_08) and then the problem. Next step is to enter the passwords of the OS users, j2eadm and SAPServiceJ2E. But, I have no idea what these passwords are and/or where to maintain them. Anyone an idea or suggestion/ Thanks, Tiest.