[ubuntu-in] UNR on macbookpro 5,1

[Linux Lingam]

dear all,

hope someone on this list has a solution for this:

bought a new 4GB thumbdrive, downloaded and installed Ubuntu Netbook
Remix (UNR) based on 9.04, for generic i386.
i already have ubuntu 9.04 installed in a partition on my macbookg pro
5,1, and use GRUB under rEFIt since more than a month.

how do i get the macbookpro to sense and boot from the thumbdrive into UNR?
have also posted this query on the forums several days ago, with no response:
https://answers.launchpad.net/netbook-remix/+question/65090

thanks

regards
niyam bhushan