How to translate between custom choice type and widget items?

Question

I have a custom variable

(defcustom myvar ....
  :type '(choice (const :tag "foo" 1) ...))

and I need to map it to

(widget-create ...
               '(item :tag "foo" :value 1)
               ...)

Obviously I can write something like

(mapcar (lambda (item)
          `(item :tag ,(third item) :value ,(fourth item)))
        (rest (custom-variable-type 'myvar)))

but I was wondering if there is something more "official".