I can't definitely confirm it but my feeling is that the answer to your question is "yes". If your Mac sees your RAID 0 configuration as a single logical drive in the Finder then I believe Time Machine can back that drive up. By default I believe that Time Machine excludes external drives but you can remove the exclusion from the Time Machine options panel. Restoration of the data is something that I'm not sure about because I've never had to restore, from Time Machine, data onto anything other than my main drive. However, you certainly could copy the data onto the replacement DAS from the Finder from your Time Machine drive. It's possible that if the replacement DAS has the same name as the DAS that died that you could do this from within the Time Machine GUI.
At the end to the day, Time Machine is just storing the data in a folder structure on your Time Machine drive. The use of Hard Links means that you can select the "Latest" folder and be assured that it contains the current version of every backed up file, regardless of when they were actually backed up. Copy the contents of the "Latest" folder for your old DAS to your new one and you are job done.
I think. I have a similar configuration for my rMBP but so far I've not actually had to restore data stored on the main external drive (not a RAID drive).
