Hey Test100,
thank you for your suggestion.

I guess that my problem was probably slightly different, but I solved it using the following steps:
[LIST=1][*]Copy NTLDR, NTDETECT and BOOT.INI to the root section of all partitions.[*]Using Vistabootpro 3.3:[/LIST][INDENT][LIST][*](system bootloader screen) select Vista bootloader; select all drives[*]Force install and click Install bootloader.[/LIST][/INDENT]Hope that this may help others.