odd... so I did some quick search seems "lame" docs doesn't say which properties it supports (you can probably get it from gst-inspect though)

    http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gst-plugins-ugly-plugins/html/gst-plugins-ugly-plugins-plugin-lame.html

but lamemp3enc docs does support quality and the other standard properties like bitrate.

    http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gst-plugins-ugly-plugins/html/gst-plugins-ugly-plugins-lamemp3enc.html