AiDownload with a VPN connected router

[canufrank]

I use a VPN on my NAS- specifically I connect to privateinteraccess using OpenVPN.
So, my NAS' IP address is random and I do not have UPnP access to the router it exits with.
Using the DDNS service on the NAS does not seem to work. I assume this is because of the above issue. Although 'Last DDNS Update' reports 'Success', navigating to the link gives an 'unable to navigate' error.
Cloud Connect does not seem to work at all. If I attempt to turn it on, the NAS clocks an 'Applying' message forever.

I do not use VPN on my router, so it's IP address is dynamically allocated by my ISP.
I use ASUSCOMM DDNS service on the router, so it can be addressed as myuserid.asuscomm.com.
I have manually set up port forwarding rules on my router for ADM, WebDAV and app#DownloadCenter on the router.

I can connect to my NAS (e.g. ADM) using https://myuserid.asuscomm.com:8001 and interact successfully.
However, I cannot figure out what to input in the AiDownload application to find my NAS.
I've tried https://myuserid.asuscomm.com:9999 (8001 and 55555)
I've tried transmission/admin for the authentication, as well as my root user credentials.
In all cases, AiDownload says 'Please check your network connection'- a supremely unhelpful message.

Any tips here?

[canufrank]

Any thoughts? I find it difficult to accept that one setting (vpn) should prevent another from working. It's not like these are 3rd party apps colliding.

Even a workaround for using AiDownload would be nice.