Hi all, I have a problem

My son (The boy with the light saber) wants OS3.9 for his A1200 and asks me everday about it. He is just 6 years now but has no other topic to talk about since several weeks. That start to become annoying, so its highest time to do what I promised...
There is however one problem. There is no CD-ROM in his C=A1200. The A1200 is connected to my big C=A4000T via ethernet and envoy3, so he has access to my CDROM-drive via the net.
How can I install 3.9 on his machine? I could copy the CD via the net onto his hardrive, but how will I do the real installation then? Is that possible from the harddisk-copy?
Any tips? Any expiriences?
Thanks in advance, selco