Thanks Aeterna , your code works fine to me ;-)
My script:
;=================================
$o_form = _IEFormGetObjByName ($oIE, 0) ; Colocar "f1" quando se tem um nome no Formulario
$oUpload = _IEGetObjByName($o_form, "txtArquivo1")
_IEAction($oUpload, "focus")
Send("{SPACE}")
Sleep(5000)
Send($caminho_arq_retorno) ; C:/Folder/File.txt
Sleep(5000)
Send("{Enter}")
Sleep(5000)
$o_botao = _IEFormElementGetObjByName ($o_form, "cmdEnviar")
_IEAction ($o_botao, "click")
;=================================