Had enough of describing that SEO links are not supported for forums with vbSEO and subdirectory in URL...
So I set up test forum myself and in next release SEO translation links will work even on forums without vbSEO

Right now I have tested SEO links on forum without vbSEO and with subdirectory un URL. With vbSEO it will be working as soon as I get testing license from vbSEO stuff.
EDIT:
And disappointing news for vbSEO users with forums with subdirectory in URL - vbSEO staff will not give me testing license, because my update license is expired. I spend lot of my time for you guys, sorry but I will not spend also my money on something what I made for you for free
So once again - who wants it working in this configuration have to set me up test forum

Otherwise I have no possibility to test it