I've tried everything but still can't figure out how to make this happen. Is it even possible?
What I want is the summary to always be visible in the grid and not scroll down with the data.

This is the code I'm using to create/add the summary, which is nothing special, it just seems that in the end I should be able to somehow add it as a fixed row - but I can't figure out how.

// formatting the summary
totalSummary.DisplayFormat = "{0:$#,###.##}";
var summaryOverride = totalSummary.Band.Override;
summaryOverride.SummaryFooterCaptionVisible = DefaultableBoolean.False;
summaryOverride.BorderStyleSummaryFooter = UIElementBorderStyle.None;
summaryOverride.FixedRowStyle = FixedRowStyle.Bottom;
summaryOverride.FixedRowsLimit = 1;
//e.Layout.Rows.FixedRows.Add(); ?? can we lock the summary here?
}