By federal laws, Volvo only has to supply info for limited fuel system codes through OBDII and thus they don't do anything more than that for the aftermarket or owner him/her self.
All the other info is only available through Volvos own tools, in '98 and earlier it's through their VST and '99 on up it's through their Vadis PC only in Volvo dealerships. They will never make it easier for the aftermarket or owner to do anything themselves and by doing it that way, they've guarantied that these cars will return to the dealers for service. It was very well thought out, no mistake or oversight. The only way around that, if you're unhappy about it, is to buy an older Volvo or other type of car. What Volvo's done isn't really all that unusual and these days the same methods are being used by other manufacturers as well. I know that BMW's done this long before Volvo ever did.

Btw, with the newer '00 on up cars, there's no way that any aftermarket laptop program will ever be able to DL software into your Volvo as ALL Volvo software comes directly from Volvo through their own intranet, not available to the public.