Bringing an Ice>Link Plus up to a newer version?

[X5Sport]

I have looked through the threads but can't see anything obvious with the answers I need. If it is there I'm sorry.

Here's the scenario.

I have a 2005 E53 with the MkIV Nav system, head with a cassette player (why did BMW do that in 2005??!!) and CD changer and no DSP.

I have an ICE>Link plus system installed with a long cable from the connectors under the trunk floor, via a small pcb adapter to an angled bracket up front and the 1st generation iPod Photo (2004 model) with a colour display.

I would like to bring the whole system up to date as my iPod is showing it's age (battery reliability is beginning to be an issue) and will probably buy something like an Iphone4 or 4G Ipod touch (when it's out later in the year). My car already has the built in Siemens (?) phone system with the handset in the armrest and SIM holder, so I'm really only concerned with the music playback capability.

What hardware/wiring do I need to replace to update the system to use the latest generation iPod/iPhone? Indeed can I use any of the currently installed ICE>Link Plus wiring/parts? Do I need to remove the existing system completely (in which case has anyone got the de-install instructions to revert the wiring to factory using the CD changer?). Do I need to start again?

I'm sure I can't be the first to try this, or at least wanting to do it, but I can't find a clear list of exactly what I would need to do and what parts need to be removed, added, can be used?

Any of the expert installers have a guide?