Dim oHttp
Dim strResult
Set oHttp = CreateObject("MSXML2.ServerXMLHTTP")
oHttp.setOption(2) = 13056
oHttp.open "POST", SOAP_ENDPOINT, false
oHttp.setRequestHeader "Content-Type", "application/soap+xml; charset=utf-8"
oHttp.setRequestHeader "SOAPAction", SOAP_NS + "/" & SOAP_FUNCTION
oHttp.send SOAP_REQUEST

Dim oHttp
Dim strResult
Set oHttp = CreateObject("MSXML2.ServerXMLHTTP")
oHttp.setOption(2) = 13056
oHttp.setOption(3) = "certificate store name/friendlyname of certificate"
oHttp.open "POST", SOAP_ENDPOINT, false
oHttp.setRequestHeader "Content-Type", "application/soap+xml; charset=utf-8"
oHttp.setRequestHeader "SOAPAction", SOAP_NS + "/" & SOAP_FUNCTION
oHttp.send SOAP_REQUEST

New-SelfSignedCertificate -DnsName "ServerXMLHTTP", "ServerXMLHTTP" -CertStoreLocation "cert:LocalMachineMy"

Dim AuthToken: AuthToken = "<Base64 encoded version of ClientId:Secret>"
Dim Http: Set http = Server.CreateObject("MSXML2.ServerXMLHTTP")

With Http
    Call .Open("POST", "https://api.sandbox.paypal.com/v1/oauth2/token", False)
    Call .SetOption(3, "LOCAL_MACHINEMyServerXMLHTTP")
    Call .SetRequestHeader("Content-Type", "application/x-www-form-urlencoded")
    Call .SetRequestHeader("Authorization", "Basic " & AuthToken)
    Call .Send("grant_type=client_credentials")
End With