Hi Peter,
can't you create a symbol from your extracted view, like creating a symbol from a schematic view? (Currently, I have no layout license, so I can't check myself). May be this is even possible from a schematic window (Design -> Create Cellview -> From Cellview... -> Cellview From Cellview; in the From View Name box exchange the default schematic against extracted.
If this doesn't work, I just can tell you how I did this for an already available model netlist file (created by any netlisting tool from Cadence, Calibre, etc.), pls. s. the PDF below (use Tools from the CIW).
HTH! Rgds, erikl
PS: I forgot to mention that you must create a spectre view which is achieved by copying the symbol view from within the library manager to a spectre view.
Also, may be, see this thread.