PKI - LDAPS / KDC Certificate with Certreq private key not exportable

I try to automate cert requests for LDAPS certificate. When i request the my cert template the certificates private key is exportable. But never, when I try with certreq. 

This is my Inf:

[Version]Signature="$Windows NT$

[NewRequest] 
; At least one value must be set in this section 
Subject="CN=dc01"
KeySpec=1
KeyLength=4096
Exportable=TRUE
ProviderType=12
RequestType=PKCS10
KeyUsage=0xa0

[RequestAttributes]
CertificateTemplate="KDC_TEMPLATE"


[Extensions]
_continue_ = "dns=dc01&"
_continue_ = "dns=dc01.mydomain.dom&"
_continue_ = "dns=mydomain.dom&"
_continue_ = "dns=MYDOMAIN&"
_continue_ = "dns=ldap.mydomain.dom&"

Then I try
certreq -new c:\_scripts\request2.inf c:\_scripts\result.txt
certreq -config pki.mydomain.dom\myCERT-CA -submit c:\_scripts\result.txt c:\_scripts\certificate.cer 
certreq -accept c:\_scripts\certificate.cer 

I got a powershell script to put the cert to NTDS Store.

But the private key ist never exportable when I script this, only when I use MMC an request manual.

Does anyone has an idea, what I do wrong??