RESOLUTION
For Sitebuilder v.3.x:1. Find info.xml file for appropriate template <SB_ROOT>/htdocs/templates/<template_name>/info.xml and change 'category' name to new existing one.
2. Update templates by running:
sb_config --update_templates For Sitebuilder v.4.0:
1. Find info.xml file for appropriate template <SB_ROOT>/htdocs/templates/<template_name>/info.xml, change 'category' name to new existing one and increase 'version' parameter from 4.0.0, for example to 4.0.1.
2. Update templates by running:
sb_config --update_templates Where <SB_ROOT> - Sitebuilder installation directory.