you have a few options;
you could populate a vacant +30 (perm live) slot on the internal fuse board if you purchase the correct pins etc. and run a new circuit to the ciggy lighter.
you could use an "add-a-circuit" fuse tap to create a new +30 connection to the ciggy lighter - just be sure that the circuit you piggy back off is a non essential system (i.e. not ABS or similar)
or if you are handy with a Soldering iron, you could hard-wire a Fused line from the Fuse box perm. input to the ciggy lighter.
or at least this is how i would do it...

not sure if this is easy enough, but happy to help if i can.