As monks already noted, there are two possibilities:

• they encoded source and stored it to binary
• they compiled and stored compiled binary to executable binary

I want to add such an information that in 1st case (which is most likely to what they did) you will get their source after decompiling;
in second case you will get another source that will differ from original source: comment will be lost, variable names could be lost, and so on.

You can drop it to me by vkonovalov at spb dot lucent dot com, and I will try advice further.

This is not trivial task however.