Active primary key on zip/postal codes_AX 09

On the AOT, we opened the table addresszipcode to identify the primary key of this table.
There is 3 indexes possibles: ZipcodeIdx / CountryRegionZipCodeIdx / CityIdx

http://msdn.microsoft.com/en-us/library/aa586852(AX.10).aspx

Each of them gets the status allowduplicate:YES

We tried to change the status allowduplicate: YES to NO with the CountryRegionZipCodeIdx.

But when synchronize of the table, there is a error message.

“Cannot execute a data definition language command on ( ). The SQL database has issued an error. Problems during SQL data dictionnary synchronization. The operation failed”

So we change again the status of the allowduplicate : NO to YES.
No error message but it doesn’t resolve my code postal duplicate control

Does anyone had already done a “code postal control duplicate” by an another way?