The only way to install jersey´s without overwriting existing is to rename the jerseys you want to install. There two different jerseys ingame and in start menu. Ingame jersey have three parts number, letter and uni.fsh. So if there are three jersey´s in the game yuo have to rename the jersey to uniXXX_03.fsh , lettersXX_03.fsh and numbersXXX_03.fsh (00 first, 01 second, 02 third jersey and so on). With menu jerseys there is more to do because you have a big.file for ex. JERS_XXX_00.big. At first you have to rename the big.file, second open big.flie with bigGui and rename all files inside (const, apt, ebo and fsh). Aftre that you have to extract ebo.file and open with hexeditor. In hexeditor scroll down to last row. There is a line with jers_xxx_021 (that´s third jersey), so you have to change to jers_xxx_031 for fourth jersey. Save ebo and install to big.file. Rebuild big. And then you have to change Numder of jerseys in NHLview to 4. Input inthe game with toolbox and now you have install jerseys without overwriting the before existing jersey.