Okay, this is a little tricky to explain, but I'll do my best...if you pry apart the boot at the top of the strut (between the mounting plate at the very top, and the top coil seat), you'll see the top of the piston shaft in there. If you rotate the assembly, you'll notice that the shaft is flat on two sides. You can fit a wrench (I think it was a 23mm on my GT-S) into the two slots, and brace it on the garage floor while a buddy--or in my case my wonderful girlfriend--uses a breaker-bar socket extension on the head bolt.
Um, that may not be super-clear to everyone, but I hope it helps...
__________________

1990 5spd V6 Camry (Still kicking at 393,000km) 1991 Celica GTS -- Pappa needs a 3SGTE...and AWD for all this friggin' snow
Honda my A$$, you just can't kill a Yota...