variable Component name

Hello
I'm trying to use a component and part of my code is:
----------------------------------------------------------------
for i in 0 to n-1 loop
for o in 0 to n-1 loop
for p in 0 to n-1 loop
if (o-p = 32) then
bf(i): butterfly port map(s(o),s(p),w(0),g1(i);g1(i+1))
end if;
end loop;
end loop;
end loop;
-----------------------------------------------------------------
but I can't set the name of component "bf(i)" and I can't set a static 
name either, because it's going to make as much component as needed by 
defining n by user.
So my question is how can I do this.
Appreciate your help.
Best Regards.
Arsalan