That sounds frustrating and understand where you're coming from, trust me on that. I would contact Huawei and see if they can provide you with the OIDs for the metrics you need, and then create a Custom Poller in the SW Web Console using those OIDs, or a Universal Device Poller, if necessary. But first you need to verify that the MIBs for those products are in the SolarWinds MIB database. If they aren't, you could get Huawei to send you the MIB for your products and then open a ticket with SolarWinds Tech Support to have them compile the MIBs and insert them into the SolarWinds MIB database.
Unfortunately, I don't know off the top of my head how to verify that a particular MIB is in the SolarWinds MIB db. I know that the db is located on the SolarWinds application server, but don't know the folder location. I've contacted SW tech support in the past and had them check for a MIB in the db for me.
I may just be telling you stuff you already know, so I hope this helps.