Raw device questions... OR Tech support says we are wrong

I've been following the numerous threads about setting up an Informix database (v7.20UC2) on a HP workstation (J200 running hpux 10.20) and was hoping someone has the definitive answer to the question: "Do you need to specify an offset into a logical volume when using the logical volume managers raw device (ie. rlvolN)?" OR "Does HP-UX write partition (ie logical volume) information or disk drive information on the drive that could be destroyed when using the raw device driver (ie. rlvolN)?" HP tech support said absolutely not!! Informix tech support said this was dependent on the OS and the way the OS manages disk drives and partitions. Now, I'm a little confused and a lot nervous!!!! The tech support from both companies said no offset is needed in the raw disk partition when using the LVM's character device driver under HP-UX 10.20, BUT I've read several posts where DBAs have destroyed their disks under this scenario. HELP!!!!!!!! Eddie