FlexPhraser steps are not available as parameters

I’m trying to create a macro in the Macro Page Designer to control a FlexPhraser.
Instrument parameters usually show up in the Paramslist, and can be connected to a gui control.
However, the FlexPhraser Step On/Off switches (in fact, most controls in the bottom section of the FlexPhraser) do not appear in the Paramslist, so there’s no way to connect them to a macro gui control.
In the (macro designer) Basic Controls, there is a FlexPhraser control that evidently connects as one overall control (the Arp page of the Hot Brass macro has an example of that).
However, I’m trying to turn on/off the individual steps (similar to the Beat Box macro, which is unfortunately locked).
Does anyone know if it’s possible to get access to these individual steps?