Hello Matt
MY RF3 handbook suggests you should not tow anything heavier than your Stepwagon - the weight of a 4x4 RF4 is 1540 Kg - not sure if this is gross or nett weight though. Your is a RF2 so maybe the best thing you can do is buy a handbook translation via this website:
http://www.click2add.co.uk/en-gb/dept_218.html.
You can get some data here too: [url]http://honda-stepwgn.info/specs/1999_may/specs_w_rotary_anti-seat_seat_modif2/
[/url] which suggests the curb weight is 1560 Kg.
Sorry can't help any further. let me know how you get on.
Cheers
Lewis