I have seen similar questions but none seems to have answers. I am hoping that as time passes someone has figured this out. Currently I have some APC devices that require their certificates to uploaded in the .p15 format. I had scripted a way to do this using their NMCSecurityWizardCLI program for our 1000 devices. This reuired me to to use the NMCSecurityWizardCLI to generate a key and CSR, then get the csr signed by the CA into a CER file, then to combine the CSR and the originally generated key using the NMCSecurityWizardCLI and finally using PSCP upload that file to the device.
The issue is that my company has switched to a third part program that generates a key and CRT file itself and does not allow uploading of CSR files to be signed. As well as security policies are now in place that prohibit sending CSR files to the CA directly as we used to do.
There has to be some way (hopefully in windows) to create a PKCS15 (.p15) certificate using the key and CRT that is gotten from the new site to be able to upload them to the APC devices.
I have looked into OpenSSL and other programs with no luck