Umm, Texas is a rather (heh) big state, you know. Travis county (where Austin is located) is about 4.5 hours away from Bill Burkett and that fateful Kinkos in Abeleine.
I for one do not think that Burkett created the memo's. He understands the Guard and it's lingo, his creation would have been harder to detect. Maybe someone gave him the memo's but I don't think so, why drive so far?