sunset, I don't know why you say that..since Fed Cup semi's are after the last tournaments in the season.
Glenn, Belgium is trying to get the finals (semifinals and finals are in the same place). We never played USA at home, so I think Belgium has a decent chance to get them. Since it is at the end of the season, I don't think the players care about what surface it is (it wouldn't interfere with their preparation for other tournaments). If they want to have a good chance against the USA, they should pick clay.