Setting Attribute msPKI-RA-Application-Policies on a certificate in Powershell

Having followed the instructions on this thread https://social.technet.microsoft.com/Forums/en/winserverpowershell/thread/347acc93-8352-4535-ab1a-23ebd49eea22 i have got stuck trying to set the msPKI-RA-Application-Policies attribute. 

I have been trying

$NewTempl.put("msPKI-RA-Application-Policies", "msPKI-Asymmetric-Algorithm`PZPWSTR`RSA`msPKI-Hash-Algorithm`PZPWSTR`SHA256")

However it is not recognising the grave accent characters when then outputting the certificate temple to a file using:

certutil -dsTemplate -v <CertName> > c:\cert.txt

Thanks in advance.