Hi,
you can do this with a little CSS modification something like:
.product-field-type-A span.product-fields-title strong {
display:none;
}
(basically you are going to add this CSS rule to ANY css file that gets loaded to your website)
You can use the "firebug" plugin to get the most proper Element Class chain to hide the correct element (custom field title in your case) though.
To see where to download firebug and how to use it, refer to this page:
www.flexiblewebdesign.com/forum-virtuemart-2-template-puremart-support/342-using-firebug-for-customization-or-troubleshooting
Regards.