Hi,
Are you only seeing this with Centos? Do you mean the ECM interface (cdc_ether), or the Rmnet interface (qmi_wwan), or does the whole USB device disappear? (lsusb -t might help answer that question). And does it return (cycling), or disappear until power cycled? If the interface is cycling, a console log from the WP console port might help diagnose. If the issue seems to be specific to a single USB interface like ECM or RMNET, a host log from enumeration to failure might be more informative.
I haven’t tried your configuration myself yet. I’ve seen some comments in other forums that describe ECM issues related to modemmanager running. They’ve been reported on newer Ubuntu, though, so I’m not sure that’ll apply here. I would expect that issue to apply to WP7502 as well, though.
Ryan