how to create a database instance in HSQLDB

hi all,
I have two applications (J2EE applications) running on JBoss 4.0 and Hsqldb as the database. The problem is , im having a table UserInfo(say) for each of the application. ( but ofcourse the column values are different). and the requirement is that i have to deploy both the applications on the same Jboss. So i need to create two seperate instances of the database for each of the application. I tried creating two seperate users(with admin privileges in Hsqldb) and creating the table of the same name UserInfo(say)under each user respective to the corresponding application, but does not allow me to create so. So how should I go about resolving this issue..
put in simple words, how to create instance of database in hsqldb

thanks in advance
pravin