How to generate Pusher authentication string from VBscript?

Please see this post for the same issue in bash.

Here is my main code:

loadFile "md5.vbs"
wscript.echo "md5('test') = " & md5("test")
loadFile "sha256.vbs"
wscript.echo "sha256('test') = " & sha256("test")

method = "POST"
app_id = <redacted>
key = "<redacted>"
secret = "<redacted>"
tstamp = datediff("s",#1970/1/1#,dateadd("h",5,now()))

data = "{""data"":{""message"":""hello world""},""name"":""my_event"",""channel"":""test_channel""}"
path = "/apps/" & app_ID & "/events"
query = "body_md5=" & md5(data) & "&auth_version=1.0&auth_key=" & key & "&auth_timestamp=" & tstamp
sig = sha256(method & vbLf & path & vbLf & query & vbLf & secret)

url = "https://api.pusherapp.com" & path & "?" & query & "&auth_signature=" & sig
wscript.echo url
dim xmlhttp 
set xmlhttp = Createobject("MSXML2.ServerXMLHTTP")
xmlhttp.Open method,url,false
xmlhttp.setRequestHeader "Content-Type", "application/json"
xmlhttp.send data
WScript.echo xmlhttp.responsetext
Set xmlhttp = nothing

md5.vbs can be found here and sha256.vbs here.

I get this error:

Invalid signature: you should have sent HmacSHA256Hex("POST\n/apps/(redacted)/events\nauth_key=(redacted)&auth_timestamp=1471291494&auth_version=1.0&body_md5=(redacted)", your_secret_key), but you sent "(redacted)"

(code edits: Added secret to sig, changed crlf to lf)