You'll need to load a newer version of the OS compare to what's currently fitted.

NavCoder will tell you the current version (but you cannot see that yet!).

So get the Resler interface, and you may want to make a cable. I use clip leads and clip onto the loom connector that sits beside the CD changer / amplifier in my E39. Your's will be a bit different, as you have a Euro E39. Mine is a Japan E39 - my nav is mounted differently.

Let's carry on off-line - I'll email you