well you just need to rename the data of the new set with the name of the dp set... but since i forgot which number the dp set got i cant tell you exactly which number you have to change but i can give you an example:
Well if you would like to replace the leather set you first have to know the set id. In that case it would be 5. Next you have to know that the items at the files got always the ID + 1 ! and you need to know how the names are. Ok its pretty simple the names are like that ArmorMale6, PantMale6, BootMale6, GloveMale6, HelmMale6.... So you would just rename the names of the other set with the names of the old set (ITS ALWAYS ARMORMALE and so on just the number is different). and just rename the bmd files! if there are ozj files just leave the name as it is and cioy them into the right folder. (Sets are at the Player folder)
But its stupid to replace a set since you can add new sets to your server...