SignCertificateParametersMBS.AuthorityKeyIdentifier as String

Var param As New SignCertificateParametersMBS

param.subjectKeyIdentifier = "1f2a3c4b5d6e7f89aabbccddeeff001122334455"
param.BasicConstraints = "critical,CA:TRUE"
param.KeyUsage = "critical,keyCertSign,cRLSign"
param.authorityKeyIdentifier = "keyid:always,issuer"
param.expireAfterTime = 31536000 * 2 // 2 years

You need property key usage and subjectKeyIdentifier values to have this one work.
(Read and Write property)

SignCertificateParametersMBS.BasicConstraints as String

Default is "CA:FALSE".

e.g. "critical,CA:FALSE", "CA:FALSE", "critical,CA:TRUE"
(Read and Write property)

SignCertificateParametersMBS.CSR as String

(Read and Write property)

SignCertificateParametersMBS.expireAfterTime as Integer

default is 31536000 for one year.

Expiration time in seconds.
(Read and Write property)

SignCertificateParametersMBS.ExtendedKeyUsage as String

e.g. "critical,serverAuth,clientAuth"
(Read and Write property)

SignCertificateParametersMBS.KeyUsage as String

The default is "digitalSignature,keyEncipherment".
(Read and Write property)

SignCertificateParametersMBS.NameConstraints as String

(Read and Write property)

SignCertificateParametersMBS.RootCert as X509MBS

(Read and Write property)

SignCertificateParametersMBS.RootKey as PKeyMBS

(Read and Write property)

SignCertificateParametersMBS.serialNumber as Integer

(Read and Write property)

SignCertificateParametersMBS.SerialNumberHex as String

Var params As New SignCertificateParametersMBS
params.SerialNumberHex = "AB12CD340123456789AB12CD340123456789"

Maximum 20 bytes, so as hex string 40 characters.
(Read and Write property)

SignCertificateParametersMBS.SubjectAltName as String

Lists DNS names or IPs.

SubjectAltName provides the X509v3 Subject Alternative Name and could e.g. be "DNS:example.com,DNS:www.example.com,IP:127.0.0.1"
(Read and Write property)

SignCertificateParametersMBS.SubjectKeyIdentifier as String

Default value is "hash".
(Read and Write property)