The units has 2 DSPs and can run two presets at the same time. It's very important to understand that routings, presets aspects and user needs are strictly correlated.
We have provided a number of presets in which a variable number of mono/stereo/combo FX are available on different channels. So, if a routing is set so that the 2 DSPs are in parallel, you may load the appropriate presets (those made for such task) to have stereo and mono fx on separate channels. This will allow you to use software Aux Sends/Returns as you asked for.
In addition to this, you can always create/modify resets at our needs, using our Vsigfile Editor.
all the best
I
