Thanks for the reply RAF, for the odd occassion I am in the car without my phone I would like to be able use the car sim for calls etc. When the phone is not in the car I have no contacts. I can manually enter them but don't fancy inputting nearly 100 contacts though the MMI.
Ah OK, now l understand what your trying to do.
You actually want to be able to use both SIM cards independently to make calls, but effectively using a common directory/contact list.
When you first connect your phone to the MMI Bluetooth, it automatically downloads all the contacts to the MMI directory, however there are three different types of contact storage.
One is bonded to the mobile phone - the MMI SIM Card directory - which is only visible when that specific phone/SIM card is connected to the car.
One is contained within the Mobile Phone only - on the SIM card - and visible on the MMI (when that phone is connected) but not its not downloaded to the MMI.
The final type of contact list is what Audi calls the "Public" directory - any contacts stored here can be accessed by any SIM, including the built in one, and up to 4 phones connected by Bluetooth. This one can make using the directory via MMI quite complicated, as when you have the primary phone connected, and also have the primary phone contacts in the public directory, you end up with double entries - because the MMI accesses the SIM card directory as well as the public directory - it effective merges both while the phone is connected via Bluetooth. And if like me you have multiple numbers stored under a single name (I.e. home number, mobile number, office number) you end up with six separate entries on the MMI directory which makes everything very messy.
I've not used the "public" directory myself, as I use my inbuilt SIM just for data, and my mobile for everything else which keeps the directory somewhat tidy. These is a reasonable write up in the MMI User Guide, page 51 onwards.
God luck!