It does http://permalink.gmane.org/gmane.comp.web.haproxy/8134 Last I heard, it was buggy unless you used a specific build from April http://blog.exceliance.fr/2012/04/13/enhanced-ssl-load-balan... but it may have improved since.

+1 If it did, that'd be really, really helpful.

The spec is pretty simple, I don't know why SSL implementations leave it off. :(