Bob, you are correct, eVDSDs are only approved as a night visual distress signal, that is why in the package for both of the Sirius Signal products, the one color C-1003 and the two color C-1002, we include a Daytime Orange Distress flag that is USCG Approved as a Daytime Distress signal.
At this time there is no SOLAS standard for an eVDSD.