The current TeX4ht distribution is tex4ht-1.0.2005_06_23_0719, which seems to contain quite a lot of fixes and enhancements. Just copying the ebuild for 20050406_p1623-r1 works fine here. However, the attached patch contains some minor changes.
Created attachment 61933 [details, diff] 20050406_p1623-r1 -> 20050623_p0719
Thanks for the report. I added tex4ht-20050701_p1825.ebuild to CVS.