Adding deals to leads

Adding deals to leads

Is there a way to add a deal to a lead that hasn't been converted to a customer? I track sales success by the value of potential deals associated to leads not customers! 

My workflow is as follows;

Cold Lead >> Warm Lead (with quote attached) >> Hot Lead >> Customer

But Zoho doesn't seem to allow the flow to work like this as you can't add a quote to an unconverted lead??