[arch-general] Problem connecting Sansa e250 with Arch

The Sansa e200 series can connect either via MTP or MSC. With the help of libmtp I can connect via MTP, but I need to be able to connect via MSC.When I booted an Ubuntu 7.10 LiveCD it worked fine, so the problem is with Arch, or at least my install of it. I suspect it's a udev or driver issue, but I'm not sure. Thanks