currently i can either only change playback settings in the xfce4-mixer or playback and capture settings aren't separeted clearly to the user, i'm not sure which is true. i'd like to have sth like alsamixer does, which let's you view either playback sliders, capture sliders or all of them. now i don't think that all should be very usefull, but i miss capture settings (as i said, either they aren't there, or i haven't found them ;)) if you already have the capture sliders available, please tell me where they are to be found...
the current mixer design doesn't allow that. There's a new gstreamer based mixer (by Jannis Pohlmann <jannis@xfce.org>) in trunk, maybe ask for it to be included there?