Hi Zoeanne,
If u really want to use wires, make sure they are enclosed within plastic or rubber tubings, otherwise, u might scratch the paint of the car?
As far as I know, I think if u make a loop wide enough for the handles, & pass them thru when securing the deco, they shdn't fall off when driving. Only when u pull the handles when opening the door will they have the opp to fall off, if not they ought to stay? Maybe to be more secure, u can use blue-tack too?
To secure your roses to the (satin/plastic?) ribbons, u prob need to sew/twist the wires of the roses to the actual ribbon for securing on the handles... Hmm, u understand??
Has ur FH been a xiong-di & deco a xiong-di car before with those stuff supplied by a BS? He prob might know how it works better than i do.. Or ask any of ur bro/fren/relative who might have been a xiong di & done up the deco for their car, they wld have a clearer picture how it is done