Disclaimer: haven't tried this myself
(yet
)
An alternative for accessing your email via the web could be a web rendering proxy. You would need to set up this proxy on a device like a Raspberry Pi or a laptop and configure your MobilePro 780 to connect through the Pi. The modern web is rendered into a sort of image with links mapped onto it, so it's only adequate for accessing text material or images, I'm not sure how well video works
(if at all
). The upside is that you don't need a modern browser on your device and only need to configure it to use the proxy; all the installing and fudging happens on the Pi.
Here's the link to the github page for the software, I'm afraid google will be more help than myself for the rest
https://github.com/tenox7/wrp