I really hate when this happens. I released a sqwebmail vacations mode patch just two weeks ago... And guess what... Today browsing the net I found a new sqwebmail version.
Fortunally no big changes in the code so I adapted the patch in a few minutes.
I modify the this patch to make it compatible with both versions (5.1.2 and 5.1.3), I don't know if it works in older versions.
Ok, here I leave you the patch:
See you around.