you COULD use the safety start switch to merely power the field on a solenoid, and hav ethe solenoid power the starter... same end result. ust adds in more wireing and more conenctions..
no diagram needed... ps.. what type solenoid you using?
auto 6v? just understand where the solenoid type you choose gets it's ground.. and where it wants hot.. then wire the big studs accordingly.. ie.. bat and starter..