I need to recompile nHibernate to use Log4Net version 1.0.2.10. I was able to recompile without problem however other component using nHibernate stop working because the strong name were different. When I recompiled with the new version of Log4Net I also sign the nHibernate dll as mentioned in the download section. However, this result in a different public key token. Is is possible for me to recompile and sign but to keep the old public key (154fdcb44c4484fc)?

Use a binding redirect in your app.config or web.config

No, it's not possible. As grennis suggested, you can use a binding redirect in the application configuration file, by keeping the original NHibernate but specifying that log4net 1.2.10 should be used instead of 1.2.9.