ESXi 5.1 scripted install error

I am performing a scripted install of ESXi 5.1. My custom install is located on a bootable external USB stick and it installs it to a USB Flash Module (an internal USB) device.

My ks.cfg has following lines:

keyboard 'United Kingdom'

# Install on the internal USB drive and partitions HDDs

install --disk=mpx.vmhba33:C0:T0:L0 --overwritevmfs

#Clearing the partions

clearpart --firstdisk --overwritevmfs

#Creating new partiotion on localdisks

part DataStore1 --onfirstdisk

It installs fine majority of time on majority of time but fails sometimes when I try to reinstall the server again. The error I am facing is an installer not being able to find mpx.vmhba33:C0:T0:L0 and suggesting mpx.vmhba34:C0:T0:L0 and mpx.vmhba35:C0:T0:L0.

I am wondering what does that detection order is depends on?

Thanks in advance.