ants load trila version

i installed the ants load trial version yesterday.
.once i completed the installation, i got a mail stating that i could run 10 virtual users.....but am able to run only 5 users...
its giving a dialog box saying that " this edition supports only 5 virtual clients"
i need to simulate atleast 10 users..
so whether i have to reinstall the tool or could u say me the procedure to test 10virtual users by using this trial version???