Informix on AIX using logical volume

hi, our company provides backup service for a client runnig Informix-online v6(?) on RS/6000 950 with AIX v3.2. we have little knowledge on AIX and none on Informix. here is the question: with every physical disk, the client create a volume group and then partition the volume group into logical volumes of certain sizes. some of these logical volumes will be used as raw disks for storing informix database. because the disks size of our machine are different from their disks and our total disk space is less than theirs, to save space, we want to group all our disks into a large volume group and then partition it into logical volumes efficently. for each informix volume , we will create a logical vulume with exactly the same size and name as that on the client machine. When restoring database from informix-format backup tapes, will there be any problem? we were told by the client that informix bypass AIX's logical volume manager and access the disk directly . Therefore, the approach will not work once the disk gemotry is changed. I don't believe informix is that stupid and inflexible. if this is true, we will be in big trouble. please advise me on this. Thanks Joe Lee