y-axis scale labels in auto-scale mode

[frackers]

I'm monitoring relative air pressure from a weather station and the value changes very slowly over a range of about 950 to 1100. I have the min/max values set to 900/1100.

If I use auto-scaling I get the small changes during the day taking up the whole of the vertical axis so I see them very well but I have no idea what the absolute values are since there are no vertical graduations or labels.

If I turn off auto-scaling then I get a pretty straight line but I can at least get some idea of the values even though the graduations are so course that I can only judge the value to within 10%.

Is there a way of making the graduations appear in singluar units even though the absolute values are in 3 or 4 figures when auto-scaling is on?

The link below illustrates the lack of values when in auto-scale mode.

http://gilks.ath.cx/cacti/graph.php?action=view&local_graph_id=13&rra_id=all

Thanks