I have been having problems with vbseo sitemap generator and I didnt integrate it with vbet. Vbseo team said the following:

I corrected the issue. It was caused by vB Enterprise translator. Please note that we don't advise vBSEO customers using vBEnterprise modification.
Basically our sitemaps were not working at all and Google couldnt pick them up correctly somehow. Hopefully this will be fixed soon if theres a proper problem. I have asked what the problem was and will add the response to this post when I get it