what version are you running?
manufacturers was incorporated into version 4
you can see the manufacturer listed on the product page on my site here:
http://www.netmedicalsupply.com/store/catalog/BioStim-M7-Digital-TENS-Unit-p-22161.html
live site, so no test orders please
notice the manufacturer listing on the lower left, and the ability to search for mfr in the advanced search page.
ver 4 also allow unlimited categories/subcategories
hth,
mike