create key.pem and key.pk8 from dumpkey.jar CERT.RSA???

(a) my device is not rooted and there is no way to root it currently...
(b) i want to make an OTA package that will install in the stock recovery
(c) i have an OTA that the oem has released for the device
(d) i have dumped the key from the CERT.RSA in the OTA zip to a key.pem file


Questions:

(1) How can i turn this key.pem file into a valid key.pk8 file????
or
(2) how can i use this key.pem file to make a key.pem and key.pk8 pair using the development/tools/make_key script in the android source code????

Ultimate goal is to make an OTA package that will pass the oem signature verification and install in stock recovery