TWebWaitMessage, ElementClassName and ElementId properties

Is it possible to add ElementClassName and ElementId to output TWeb WaitMessage HTML element.
Currently when I set something on these properties the HTML is rendered without values.

<span tabindex="0" style="background-color: black; opacity: 0.2; inset: 0px; z-index: 19999; user-select: none; position: fixed;"><div style="position: relative; width: 100%; height: 100%;"><img src="Unit1.wbwtmsg1.Picture.gif" style="position: absolute; inset: 0px; margin: auto;"></div></span>

Hello Support,

Can I get answer for my question?