Is there a way to use 2 lightmaps on the same terrain

Hello

I have a scene which was initially made as a night time scene, however i then used the same level, took out the lights providing the night-time illumination and just inserted one directional for the sun light. I then ran the lightmapping again, for the day scene. Everything was great at this point, however i noticed when i reloaded my nighttime scene, that its lightmap was overwritten with the new one.

My question is - is it possible to have the same terrain that is used in my day and night scene, and have an alternate lightmap for each setting?

Thanks

Steve

http://forum.unity3d.com/viewtopic.php?t=17606