On Adding leading zeros on a bus in a schematic (.bdf) file

Thank you tricky, so I was doing it the right way. But it's a little annoying !

I'm using a schematic because it's a pretty large system and I use some standard cores in it (fir, comparator,mux etc etc). So because setting the cores using a schematic is simpler then doing it by hand in vhdl I use a mixed system.

Probably there is a better way but as I still don't know it I'm working this way..

Do you have any suggestions ??