Inserting spaces or changing the capitalization itself won't insulate yourself from trademark suits. I suspect highly that he is intending to build a correspondence between his product and the "salesforce.com" product not some generic use referring to groups of salesmen.
Referring to salesforce.com's trademark is perhaps permissible if done properly.
“Salesforce” can be used when referring to the specific Salesforce business, if used in a descriptive way only. You can, for example, refer to your drink as a Coke and to your car as a Mustang.
But dfabs cannot state or imply he has any affiliation with Salesforce where no such affiliation exists. To use Salesforce in connection with his own services/goods would infringe on the rights of the Salesforce trademark holder.
That said, the separate words “sales” and “force” are generic words that can be used by anyone.