you first need to create a retrived property within the BigFix Console that will retrieve the value of your regkey. Once that is created, you can create a custom web report that displays the values of the results of your new retreived property.
Open the Console > Tools > Manage Properties > Add New
Name: POS One System Build Version (or whatever)
Relevance: if exists value “Version” of key “HKEY_LOCAL_MACHINE\SOFTWARE\IBM\POS ONE System Build” of registry then (value “Version” of key “HKEY_LOCAL_MACHINE\SOFTWARE\IBM\POS ONE System Build” of registry as string) else “”