Extra inputs for emoncms on an emonpi

I've just installed an emonpi and am using the onboard emoncms installation.

In addition to the directly connected inputs, I also have a fronius data logger, which has been monitoring my PV array for some time. This is a web-enabled device that can serve up readings over ethernet when polled.

I've set up a crontab shell script on the emonpi to pass values from the fronius logger to the emoncms on the emonpi as a feed, so I can see the solar PV on my dashboard, which works well.

The trouble is that what I want here, I think, is an 'input' or 'node', rather than a 'feed'. I need to be able to do kWh accumulation and arithmetic between inputs, which are done in terms of inputs, rather than feeds when I use 'Add Process' on a node input. I'm still going up the learning curve with this kit.

I get the impression that the emoncms on the emonpi is a cut down version, and that the ability to add 'virtual' inputs is not there. Am I understanding this right? If so, is it possible to run a fuller version on the emonpi itself? Alternatively, could I fake readings from an unused physical node, or something?

I can see alternatives to what I'm doing: hosting the data elsewhere, or using a CV to monitor the solar instead of the existing data logger, but with my configuration getting the software on the emonpi to do it all would be most convenient.

I would appreciate any suggestions.