[WD22] Send a file through Web Service (no replies)

I need to send a small file from WINDEV through a WEBDEV Web Services and save it on the server. I've tried it with a buffer, but I do not know if it's the right way to do it.

This is the code of WINDEV:

gsCertificado = fSelect("","","Selecciona un certificado", "Certificado" + TAB + "*.cer", "*.cer",fselOpen+fselExist)
bufFile is Buffer = gsCertificado

EMP_SubirCertificado(bufFile)

And this is the code of WEBDEV Web Service:

PROCEDURE EMP_SubirCertificado(bufCertificado is Buffer)

sNombreCertificado is string = DateToString(SysDateTime(),"DDMMYYYYHHmm")+".cer"
fSaveBuffer(fWebDir()+"\Certificado"\"+sNombreCertificado,bufCertificado )

Maybe it's not the right way, but it was what I thought would work.
Any information is appreciated. Thanks in advance.