what you request is called data subsetting. i havent used olite 11g but i use olite 10gr3. i guess these 2 should be similar. so please check
1) go in the mobile workbench and in the publicatiion->publication items that you created write in the sql string where user:=usernamevar
this way you declare a variable called usernamevar and you will download anything that user=usernamevar. then go in the mobileserver int he application there should be a data subsetting tab. there you will see the users that you registered to have access in the application. if you click one you will see the usernamevar. now i recommend to always use string so you could write the id of the user like '123'. this tells the olite that this user has for usernamevar='123'.
of course you can call your variable howerver you like