I feel like I might be losing my mind...but if you search the AOT for anything with double colons "::", it fails completely. I'm trying to step through the Forms\SysAotFind to figure this out but I didn't want to spin my wheels a bunch for something that might be on my system only.
To reproduce in AX 2009, select Classes\SalesTableType, press Ctrl+F and put "CustLedgerAccounts::sumAccount" in the containing text box and click find now. You can see this is clearly located in the Classes\SalesTableType\accountCust method. I've tried searching for base enums inside objects with no luck either.