Keynote / Pages / Numbers backwards compatibility

Hi,

I have purchased Keynote, Pages, Numbers from Mac App store a while ago. I have used them for a while with no issues. After the launch of Mavericks, I cannot install the older versions since currently App Store offers only the latest version of the apps without any backwards compatibility. I cannot install the new OSX since it does not work well on my older iMAC. I currently use Lion OSX.

This is a serious backwards compatibility issue. Is there any way to solve this without purchasing iWorks '09 again or upgrading to Mavericks?

Update: Some forums suggest that there is an option to install the last compatible version when pressing the "Install" button. Is this feature removed? I cannot download anything. I only get a message that "Keynote can’t be installed on “MAC” because Mac OS X version 10.9 or later is required." And that's it...