PTP Company iXBRL accounts submissions to HMRC

Have a client using PTP to produce company accounts and Corporation Tax return, for me to check over.

Was OK last year when he did it all on paper but he's getting in a flap over how it all works for iXBRL accounts, he says he's been onto HMRC's website but can't see how to submit everything that way.

I'd assumed that, as with other software (eg Iris), you produce the accounts & CT return in PTP & submit directly through the software.  Does anyone know please as I know who's going to get the job of sorting this out.