Use BCD edit in Vista. From the Linux side you need to find the file which is called grub.cnfg. This is a text file. Then go back into BCD edit and paste this text into the Menu List file.
When you install Linux, shrink Vista using itself to free up some room. Make 2 partitions, one which is small, about 512 megabytes, and the other which is the rest of the free space. Make a folder and put it into the small partition. It doesn't matter what it is called so long as you can remember it. Also, name the partition. Do NOT format either partition.
When you install Linux, use the advanced boot loader options. Do NOT write to the root of the drive or the MBR. Vista's boot repair tool is not effective. Kill the boot sector = Vista is fried, reinstall. Choose this folder in the small partition as your mount point.
Linux will install and then restart. Vista will appear with no trace of Linux. This is exactly what we want. Using a live CD such as Simply Mepis 7.0 or some other utility, copy the /boot directory to a thumb drive or put it into the Documents folder in Vista under your username. Yes, the Mepis live CDs and DVDs can read and write NTFS file systems with no modifications. Putting the text directly into menu list is risky and could upset Vista's "security" software.
Also, clean up the text when you paste it. Make sure that all the lines are straight etc. This avoids problems.