I hadn't picked up on it before I saw it mentioned in a review, that Hugh Jackman's character is Gabriel Van Helsing, while Bram Stoker's character is Abraham Van Helsing. What, if any, significance there is, I can only guess. Maybe it's a subtle way of acknowledging that it's actually a different character all together...? :)
Edit: Turns out, it's basically so that Sommers now has a copyrighted character. Abraham Van Helsing is in the public domain. Gabriel Van Helsing is not. It makes sense, but is woefully unpoetic.