I have been using httputil for a long time, and with every thing we have done so far we are building the calls using something similar to the code below
B4X:
job1.Download2("http://www.b4x.com/print.php", _
Array As String("key1", "value1", "key1", "value2"))
'Note: Notice ending / in first part of URL string
job1.Download("http://www.b4x.com/print.php/" &_
PyJoin("/",Array As String("key1", "value1", "key1", "value2")))