Sam,
I am sorry, but I have used the following sample to run tests using Curl and Microsoft Excel. The following example takes information from cells in an Excel spreadsheet, uses the data to build the Curl command, then run the Curl command, and place the returned result from Curl into the result column in the spreadsheet. I can send an example Excel Spreadsheet if you are interested.
Sub Simple()
Dim rangetoexport As Range
Dim rowcounter As Long
Dim columncounter As Long
Dim CurlCommand
Dim WSS As Object
Set WSS = CreateObject("WScript.Shell")
Dim WSSExec As Object
Set rangetoexport = Selection
For rowcounter = 2 To rangetoexport.Rows.Count
CurlCommand = "cmd /c "
CurlCommand = CurlCommand & "curl "
CurlCommand = CurlCommand & rangetoexport(rowcounter, 2) & "/"
CurlCommand = CurlCommand & rangetoexport(rowcounter, 3) & "/"
CurlCommand = CurlCommand & rangetoexport(rowcounter, 4) & " "
Set WSSExec = WSS.Exec(CurlCommand)
Cells(rowcounter, rangetoexport.Columns.Count + 1) = WSSExec.StdOut.ReadAll
Application.Wait (Now + TimeValue("0:00:05"))
Next
End Sub