Which server did you use to create the certificate? If it was IIS, you can simply export the cert to *.pfx file and use that in Xeams. Check Option #3 on the SSL certficate page in Xeams (localhost:5272/FrontController?operation=187)

If you used Apache to create the SSL cert, you will have to follow instructions on this blog. Once the cert is in JKS format, you should be able to use in Xeams