What an appalling state of affairs !
Such a situation would suggest that this is a badge engineered product that Extech neglected to purchase software rights to 
Total and utter rubbish service, not deserving of your money. I hope you get your money back so that you can spend it with on a more deserving LCR meter like the Mastech or BK offerings that you mentioned.
When I think of what came with my Mastech 5308..... batteries, tweezer probes, Kelvin clips, test slot, optical PC link cable, Software, PSU and a decent padded soft case..... now that's what I call a fully loaded LCR meter kit
Manual is still cr*p though 
Aurora
Update...
I just took a look here:
http://www.testequity.com/products/4172/
I can't believe the prices ! It appears everything that came as standard with my MS5308 is at additional cost on the Extech ! The unit spec appears to indicate that this is yet another 100kHz LCR meter that is built around the Cyrustek chipset. You could probably communicate with your LCR meter using the Mastech software as the chipset doesn't use OEM specific coms protocols. If you shine a torch into your LCD meters serial port you will see either contacts (3.5mm audio socket) or an IR LED. A simple cable can be built for the 3.5mm socket type connection, but the LED would need a simple IR receiver circuit and appropriate housing to mate with the meter. I would still get my money back and buy a more worthy brand that uses the same excellent Cyrustek LCR chipset 
I did quite a bit of research, including reading through your review and related posts. I chose this unit based on the fact I could get it from a reputable seller, it had 100 kHz test capability, and came from a well-established manufacturer.
When I first got it I was encouraged by seeing all case screws used metal threaded inserts, but things went downhill from there. This unit shares the same problem with some other meters in that it doesn't have a simple relative function. It has open and short calibration modes. You start with an open calibration, press "CAL", it counts down while it does its thing, and displays either Pass or Fail. You then short the leads and repeat the process. The short calibration would pass with the supplied alligator clips, but would always fail when using a brand new, gold plated pair of Probe Master leads. There is a separate relative function, but by
relative, they mean relative to a reference component-resistor, cap, etc.
Considering their ad stated it had an RS-232 interface and came with a battery, neither of which were the case, if I can get my money back without having to pay the 15% restocking fee from testequipmentdepot, I'll chalk it up as a valuable learning experience.
I see the Mastech on sale on Ebay for $211 including all the accessories. Your review is encouraging and I can now appreciate that it comes with accessories.
I've used the reviews and recommendations from this site to chose solid old HP power supplies, Hakko 888 soldering station, Tek 2235 scope, used Fluke 87 meter, UNIT UT61E meter and an Instek SFG-1003 generator. I'm at the bottom of the learning ladder, so it seems like I should continue to take advantage of the experience and recommendations of more experienced users.