are you doing an in-place upgrade or a migration to new devices? the f5 upgrade process will (to the best of its ability) automatically convert current configuration formats to that of the new code level. i've done migrations by both converting current config into new config syntax and moving config to new hardware/VE or by upgrading the entire config in a test environment and importing the new config to the new hardware.
are you stuck with doing a migration of old-code/hardware to new-code/hardware, or do you have other options?