FSX - How to change roof colours of Autogen houses

Hi,I want to change roof colours in FSX. In FS2004, I took for North America area, texture templates BLDB2.bmp and BLDC2.bmp, converted it to 24bit Bitmap repainted the roofs, converted it back and got new roof colours in FS.I applied the same process to BLDB2.dds and BLDB3.bmp in FSX, but there was not any change in FSX. Did I take the wrong templates, i.e. BLDB2.dds and BLDB3.bmp are not assigned to North America area ? Or is there basically any different process in FSX ?RegardsBruno