[Genome] How can I get human-chimp divergence data in hg17 and hg18 database

[wangxi]

Hi, UCSC Genome Browser Team!

I want to use the data of human-chimpanzee divergence complied from whole genome alignment. And, I noticed that there is a table Chimp Diff in hg16 database that was constructed based on human-chimp reciprocal best alignment. I want to know why the table is no longer available for hg17 and hg18 database? Is it replaced by other tables with similar content? Or would you please tell me how to construct the "reciprocal best alignment" of these two species based on the current available tables like chimp net and chimp chain and programs in you Kent source tree? Will it be difficult, since I am not quite familiar with the detailed algorithm in chain and net related  program? Or, could you tell me if there are similar data sets generated using other approaches and publicly available? 

Thanks very much in advance!

Sincerely yours,
Xi