The exchange could provide liquidity and make this trading pair more attractive, either with an automated system or manually (let someone trade market maker style with the exchange's money). Otherwise it will be stuck with the chicken and egg problem of no liquidity, no traders, no liquidity.
We have chickens and eggs by having a website that works IMO. What we need is more people willing to sell Namecoin for any price and see if we can connect them to a buyer.
Offer the Namecoin for sale on our exchange for 5-10% more than any other exchange out there... see what happens! If you get sick of waiting, withdrawal your coins. (The exchange earns a little off each withdrawal normally, so we like to see you take your coins back.)
The website works really well. Deposits count confirmations correctly and withdrawals are basically instant. I think having a website that actually works well is the best marketing a Cryptocurrency exchange can do.