How to export to RTF (Lyx 1.5.1, Mac OS X)

[Isaac Pante]

Hello,

In the version 1.5.1, the export menu requests a command to be done.  
I have two questions reguarding this:

1) where can I found the command(s) allowing me to export my lyx  
document in RTF (and for the other formats)?

2) do I have to install special packages in order to let the commands  
working correctly? If the answer is yes, which packages are requested  
and where can I find them?

Many thanks for your help!

Isaac Pante