Is there any way to book a mixed class, multi-city itinerary on aa.com? I'm looking to book BOS-LAX/SAN-BOS in late Oct/early Nov, and for my particular dates, there's very little added cost to pay for F on the SAN-BOS sector. The BOS-LAX nonstop is quite a bit more in F, and would probably be a better use of a mileage upgrade.

However, the multi-city booking tool seems to drop me into a Web 0.5 interface that doesn't seem to allow individual segment selection, let alone mixed class of service.

Is there any way around this that doesn't involve paying a telephone booking fee?