SRX 300 - How to disable transparent mode

Previously we used SRX100 and SRX110 routers.

Now we have switched to the SRX300 and there's a lot of problems getting our old configs to run on it.

It seems to boil down to this new transparent mode.

The router rejects our NAT and insists on these new IRB interfaces or it won't run. Both times informing us that it's in transparent mode.

How do we get out of this transparent mode and put the router back to the way the SRX100s used to work?

Thanks for reading