You must use bootmenu that comes with Merinstaller. Install Mer installer and then make a bootmenu .item for ubuntu /etc/bootmenu.d/ubuntu.item for example
ITEM_NAME="Jaunty on internal card, p3" ITEM_ID="Jaunty on internal, p3" ITEM_DEVICE="mmcblk0p3" ITEM_MODULES="mbcache jbd ext3" ITEM_FSTYPE="ext3" ITEM_FSOPTIONS="noatime,ro" ITEM_LINUXRC="linuxrc"