Just hope you are talking about license plate frame that is in Europe different than for non EU countries. There are two ways to go:
a) just drill the plate to bumper/frame b) there are for sale here some kind of plastic underlays. Those underlays you need to drill to bumper/frame and license plate is just "clicked" into this underlay...
I can try to find some pictures if you need them later.
No more replicas... This is evolution... This isSS-four:)________[Featured Celica of 6gc.net @ 2010]_________
Directly drilled (I believe there are holes for OEM frame to use):
Here is one version of that plastic underlay (license plate is not drilled)...
And this is second version of underlay... (very popular also for rear). You can use advert on it so many companies here offer this for free.
Also (but I can nor find ST205 pic) there is some kind of OEM front frame (the same as for non EU versions). But you need to use bolts to fit plate as well.
No more replicas... This is evolution... This isSS-four:)________[Featured Celica of 6gc.net @ 2010]_________
This is OEM rear frame for European Celicas. I had it on my first Celi as well and as you can see I used that "second version of underlay" there...
I believe part number (in white) is 75082-20280-A0 and if you want it I can ask around. 95% of Celicas has it here so there is a chance someone parted out Celi and still have it.
No more replicas... This is evolution... This isSS-four:)________[Featured Celica of 6gc.net @ 2010]_________