The website is not complete. The weight is indeed 600kg for LSA purposes, that's why it says 1320 lbs (LSA). Edition 1 of the design was indeed limited to 600 kg.
Edition 2 issued July 20 2010 and subsequent editions have a design MTOW of 650 kg (1440 lb)
Here is a list of the parts that were beefed up or added by edition 2:
Model: STOL CH 750 “GROSS WEIGHT INCREASE” KIT PARTS LIST
Parts List: 08/10
Revised Pick-List:
Page 1of 1
PART NO: DESCRIPTION QTY
WING KIT
75W2-6/1 WING SPAR WEB DOUBLER t=.063 l-650mm 1R+1L
75W2-5/1 WING SPAR UPPER STRUT FITTING t=.25 2
75W4-7 I/B REAR CHANNEL ANGLE t=.040 2
75W8-1/1 FRONT LOWER STRUT FITTING WELDED ASSEMBLY 2
75W8-2/1 FRONT UPPER STRUT FITTING WELDED ASSEMBLY 2
L L ANGLE 20
AN3-5A BOLT, SL NUT, WASHER (2@75W3-3) 4
AN3-7A BOLT, NUT, WASHER (75W2-7) 2
AN4-5A BOLT, SL NUT, WASHER (2 75W2-7) 4
AN4-7A BOLT, NUT, WASHER (75W2-7) 2
FUSELAGE KIT
75F3-4/1 UPRIGHT PRE-DRILLED l=983mm t=.025” 1L + 1R
75F3-7/1 REAR TOP CHANNEL PRE-DRILLED l=1009mm t=.063” 1
75F3-9 REAR TOP CHANNEL ANGLE t=.063 l=1019mm PRE-DRILL 1
75F4-2/1 SIDE CHANNEL COVER PRE-DRILLED l=1011mm t=.040” 1L + 1R
75F4-4/1 REAR WING ATTACHMENT PRE-DRILLED t=0.1875” 2
75F4-7 SIDE SKIN GUSSET t=.063 2
75F4-8 BOTTOM SKIN GUSSET t=.063 2
75F4-9 LONGERON GUSSET t=.025” PRE-DRILLED 2
75F12-2/1 FORWARD SIDE SKIN PRE-DRILLED t=.025 1L+1R
75F12-7/1 FORWARD ANGLES l=450mm t=.025” 6
75F14-1/1 LOWER ENGINE MOUNT FITTING WELDED ASSEMBLY 1L+1R
75F14-3/1 GEAR STRUT FITTING WELDED ASSEMBLY 1L+1R
75F15-1/1 CABIN FRAME WELDED ASSEMBLY PRE-DRILLED 1
75FA10-1 BAGGAGE BACK CHANNEL t=.032 2
75FA10-2 SIDE SKIN DOUBLER PRE-DRILLED t=.032 2
75FA10-3 SIDE SKIN ANGLE t=.032 2
A6 3/16 RIVETS 45
AN3-5A BOLT, SL NUT, WASHER (6@75F4-4/1) 18
AN3-3A BOLT, SL NUT, WASHER (4@75A10-2) 8
AN4-5A BOLT, SL NUT, WASHER (2@75F4-1) 4