And that is – in AX 2012 – absolutely correctly observed by the compiler. The method was present in earlier versions of AX but went missing in AX 2012 and was replaced by the method xmlMapUnitOfMeasureSymbol.
So if you use the wizard on for example on a query using ProdTable you might end up with an error telling you that this.mapPolicy().xMLMapUnitId() does not exist. Replace it with this.mapPolicy().xmlMapUnitOfMeasureSymbol() and you are good to go. It will also tell you that this.axUnitId() is incorrect which also is true. The correct method name is axUnitOfMeasureSymbol().
Once you know it … 🙂