Yes, it is possible, in the sense such that if you are truly motivated to create a WDS you can. Read the applicable instructions here:
Expand the directions until you find the link to Wi-Fi base stations: Setting up and configuring a Wireless Distribution System (802.11b/g)
Your challenge will require several workarounds, not the least of which that you will need an older, unsupported version of AirPort Utility to configure your original AEBS. In the end you are not likely to be pleased with your network's performance, even if you get everything to work perfectly.
Edit: As Bob says if the ability to participate in a WDS is gone entirely in the new Time Capsule, then it is not possible. Be grateful for that
Message was edited by: John Galt