MATLAB: Caxis with HeatMap

Bioinformatics Toolboxcaxiscolormapheatmap

I'd like to specify the scale of the colormap used for a heat map.
It seems that something like caxis would be appropriate but it doesn't appear to work. All of the examples are for functions like surf.
Is there a way to use caxis to do this, or something else that would work for a heat map?
Thanks very much.

data = gallery('invhess',20);hm = HeatMap(data);ax = hm.plot; % 'ax' will be a handle to a standard MATLAB axes.colorbar('Peer', ax); % Turn the colorbar oncaxis(ax, [-3 10]); % Adjust the color limits