It seams that some VPN servers have problem with null characted added to XAuth password` in IPsec Xauth PSK mode. This patch removes it.
I've tried this patch in OpenWrt 12.09-beta2, but it doesn't work for me.
I've got it working with Strongswan, they have addressed the same issue in this commit: http://git.strongswan.org/?p=strongswan.git;a=commitdiff;h=7d85bebc
Change is only in client side code. I hoped that google would take it from here, but I probably need to upload it to AOSP gerrit for them to notice.