Should I upgrade from D70s to D80 for Ice Hockey

Hi, I have had a D70s for just over a year now - and have really really enjoyed it. I am considering upgrading and new lenses - but would appreciate some advice. My photos are typically of Ice Hockey e.g.

http://hockey.idoine.co.nz/Nationals/2006/NZIHF_Nats_2006_Sthn_Vs_Cant_U19/target5.html
or

http://hockey.idoine.co.nz/Nationals/2006/NZIHF_Nats_2006_Cant_Vs_Akl_U16_Sat/target12.html

I typically shoot with the cheap 70-300 lens and with SB600 Flash - the EXIF info on the shots above are typical although I have tended to prefer to use ISO of 640 lately. i.e. Shutter Priority 1/500 sec. to freeze the puck and action I need to shoot at least 400th but typically 1/500. The SB600 copes well with most of the Ice Rink from center ice - by increasing the SB600 Flash to between 1.2 and 3x

My questions is around the fast flash sync - with the D80 having a 1/250th Sec Fastest Flash Sync - will I not be able to take these type or photos - or the alternative question - how will I be able to take these type of photos ?

Peter