Hi Diego,
Unfortunately the Q2 2009 version of RadChart will not feature secondary YAxis support.
That said, we are actively adding improvements to the chart control at the moment -- for Q2 we will be introducing
strict mode support (the control will respect the XValues passed as data),
categorical axis support,
LabelStep functionality, and
rotated labels for the horizontal axis. We will definitely consider the implementation of the mutliple axes feature for Q3 but we cannot commit a promise right now as we have not finalized the planning for the next release yet.
Greetings,
Manuel
the Telerik team