Fortigate 50E supported USB modem including Huawei E8372?

Support/CS have not been very helpful in advising on this as they are insisting that the former support provider log the question. That PITA aside all I am really after is confirming on whether the E8372 is supported or not? Currently it is plugged in but it is not being detected at all. The built in supported list in the 50E doesnt mention this model at all... But i was wondering if a newer firmware or similar may extend proper support. On a side note how gospel is the supported list? i.e. If its on it it works, if its not listed you're up a creek?