I haven't actually tried this in 2005, but you should be able to. Tablestyles are part of the objects collection of the dxf structure (instead of tables interestingly enough).
To find a table style, you use the named object dictionary (namedobjdict function i think) object to retrieve the database pointer and then dictsearch, dictadd and dictnext to iterate through the collection. THere' a collection in there for table styles (similiar to pagesetups in 2002, I expect) which should return an entity name for your table that you can pass to entget or entmake. Of course, at this point, it might be simpler to use vba.
I would guess it'd be something like this:
thisdrawing.tablestyles.add(bunch of params,bunch more params,bunch of crap)
Tables reference a subobject called a cell.
Anyway, the full details are in the DXF reference.
CAD Naked
John