primary key

Crappy explanation of problem: I can send data via webservice in mendix 4.0 from localhost A to localhost B and create a new object at localhost B with data of localhost A. Then I change the data at localhost B. When I want to import the changed data back into localhost A, I need a primary key. I've tried to use Autonumber as a unique identifier at localhost A and set a attribute on localhost B to Integer witch catches the autonumber. When I want to fetch the data from localhost B as localhost A I can't choose the Autonumber attribute to compare it with the primary key, which would be the integer I guess. Question: This all happens when I try to "XML mapping to domain". I would like to know how I can set a good primary key to exchange information between localhost A and localhost B. Thanks in Advance!
1 answers

Edited after comment of Bas (thanks I was wrong).

You can use a UUID. That is always a unique number.

You can use community commons randomHash for that.

Assign the UUID in an after create event and use it to update or sync data.