I've been using this classic asp ARB snippet for years... just replace the info with your own.... hope it helps:
<%
ReDim arrVars(2, 0)
Sub add(iName, iValue)
x = ubound(arrVars, 2) + 1
Redim Preserve arrVars(2, x)
arrVars(0, x - 1) = iName
arrVars(1, x - 1) = iValue
End Sub
add "x_login", "XXXXXXX"
add "x_tran_key", "XXXXXXXXXXXXXXX"
add "x_version", "3.1"
add "x_test_request", "false" 'Used for testing
add "x_delim_data", "true"
add "x_delim_char", "|"
add "x_relay_response", "false"
add "x_first_name", request("bFirstname")
add "x_last_name", request("bLastname")
add "x_company", request("bCompany")
add "x_call address", request("bStreet1")
add "x_city", request("bCity")
add "x_state", request("bState")
add "x_zip", request("bZip")
add "x_country", "US"
add "x_phone", request("bPhone")
add "x_cust_id", request("memberID")
add "x_customer_ip", request.servervariables("remote_call addr")
add "x_email", request("email")
add "x_email_customer", "false"
'add "x_merchant_email", "you@yourwebsite.com"
add "x_invoice_num", request.requestID & "-" & day(date) & month(date) & year(date)
add "x_description", "Toolshop Purchase"
add "x_ship_to_first_name", request("sFirstname")
add "x_ship_to_last_name", request("sLastname")
add "x_ship_to_company", request("sCompany")
add "x_ship_to_call address", request("sStreet1")
add "x_ship_to_city", request("sCity")
add "x_ship_to_state", request("sState")
add "x_ship_to_zip", request("sZip")
add "x_ship_to_country", "US"
add "x_amount", request("orderTotal")
add "x_currency_code", "USD"
add "x_method", "CC"
add "x_type", "AUTH_CAPTURE"
add "x_recurring_billing", "no"
add "x_card_num", request("cardNumber")
add "x_exp_date", request("expMonth") & "/" & request("expYear")
add "x_card_code", request("CID")
IF request("bState") = "MI" then
add "x_tax", "6%"
Else
add "x_tax", "0%"
End IF
add "x_tax_exempt", "false"
add "x_freight", request("shipping")
Dim qs 'short for querystring
For i = 0 to ubound(arrVars, 2) - 1 Step 1
qs = qs & arrVars(0, i) & "=" & arrVars(1, i) & "&"
Next
qs = left(qs,len(qs)-1)
Dim http, strStatus, strRetval
Set http = Server.CreateObject("MSXML2.ServerXMLHTTP")
http.setRequestHeader "User-Agent" ,"Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322)"
http.Send qs
strStatus = http.Status
strResult = http.responsetext
Set http = nothing
Dim arrResult
arrResult = split(strResult, "|", -1)
IF arrResult(0) <> "1" Then
request("arrResult") = arrResult
response.redirect "transactionError.asp"
End IF
transactionID = arrResult(6) ' Use for saving to your DB and/or confirmation email later
%>