Can't boot Acer Aspire One (150) from SDHD installed in system expansion port

I have an Acer Aspire One and I would like to boot from an SCHD card installed into the system Expansion port. It works fine when used in a USB stick. When I check the boot order the expansion port is not listed as an option. There is an option for doing a network expansion. Are there any bios updates that would read that port on startup?

Try to ask it on the acer aspire one user forum

I know that under Linpus, that port can only be used as an extension of the documents directory/partition.