Only rarely does the decision of a trial court warrant a law department either filing or responding to an appeal. Even then, most general counsel stick with the firm that litigated the case below to represent them on the appeal.
Once in a blue moon, however, strategic wisdom persuades a general counsel to bring on a firm that has a specialized appellate practice. Even so, according to a profile about such a practice at Sidley Austin, appellate counsel typically partner with trial counsel from the original firm, Corp. Counsel, Vol. 16, May 2008 at 19 (See my post of Aug. 10, 2007: virtual teams and references cited.).