CRM Link Work with custom objects in Salesforce

The CRM link module integrates well with Salesforce but you are restricted to only updating records that are either Leads, Contacts, or Accounts. Normally this isn't an issue as these are the records Salesforce normally uses. 

There are many modified versions of Salesforce that may use a custom object for storing contacts information instead of the standard ones. An example is Improvit360. This is a version of Salesforce modified for the home improvement industry. Instead of Leads, Accounts, or Contacts, it uses a custom object called Prospects.

Is there a way a custom object could be used to lookup a number instead of the standard Salesforce ones? If not, can I suggest this feature as I believe it will increase the types of CRMs this integration could work with.