Complicated Odometer Question

Hi to all.

First of all i apologize for my english.

The story goes like this:

I have a 1995 DT Manual p38 (originaly sold in Italy, so the whole system was metric)
I had a problem with the becm that i coudn't figure out at that time so i had to buy a new working becm.
I bought from a ebay.co.uk a new becm along with the key, clocks, ecu, door handle..the whole package.
When the problem occured the odo showed 154.000 KM.
The new becm/clocks show 177.000 MILES.
I know that the message center will display the highest number between the clocks and becm.
I know that UK clocks CAN'T display KM on odo/trip computer

Now, the problem:

I want to put my old clocks back just so the odo/trip computer show KM and not MILES.
The becm market is set for North America (passive immo reasons)
If i put my old clocks back what will the message center show?
Do I need to re-set the market to one that uses the metric system?
Will the becm then automatically convert miles to km?

Think you can switch the display in the BECM but you need serious diags to do it. Although someone may know different.