Can't assign percentage in ASP.NET FCKeditor control?

I'm trying to set the height of my editor area to 100% in ASP.NET like this:

fckeditorInstance.Height = "100%";

Problem is that it only accepts an integer. I even tried this:

fckeditorInstance.Config["Height"] = "100%";

But this didn't work either (it just ignores it). It's really annoying, but I don't know why the minimum height is set to 200px on the iframe, which is what is being set on the iframe:

<iframe id="ctl00_EditorNET___Frame" src="/plugins/fckeditor/core/editor/fckeditor.html?InstanceName=ctl00_EditorNET&Toolbar=Standard" width="100%" height="200px" frameborder="no" scrolling="no"></iframe>

Not sure how to correct this server side. Does anybody know?