Changing commune

We are thinking of moving from Uccle to somewhere like Waterloo and I was just wondering what this entails at the new commune? Do we have to reregister as if we have just arrived in Belgium (i.e with all our documentation) or is it a little simpler and just a case of them using our current papers we were given by the Uccle commune?

I ask this mainly because my last name is not the same as my birth name and it caused no end of hassle. In the end a legal bod from Deloitte had to get involved and got them to back down. Wonder if I need to go through the whole thing again!