I've got the same problem on a De Rosa..talked with a local welder that works with aluminum and he said he could fix it. I have to strip the paint from the area and if he is able to fix it i will get the frame repainted. Maybe look around for a local welder and see what they say. Its only gonna cost me about $40 so that is well worth it giving the frame is 2k new.
Other than Bling, what makes a De Rosa frame worth 2K?