Extend Express wireless network with another Express

[gpezzino]

I am trying to set up an airport express to extend the wireless network created by another express. The network is created by an old (b/g) model of airport express, with firmware 6.3. When I create a wireless network using express 1 there is no box with the option to extend the the network (like there is in the new n version of express). The network works fine and I can connect to it from my iPhone and macbook air.

After I create the wireless network on express 1 I go into the setup for the express 2 and choose to extend the express 1 network. After express 2 restarts it just blinks and airport utility says that express 2 cannot connect to the network.

So, can a network created from an old model of airport express be extended?

Any help would be appreciated.