My goal is to let the provider downloading a hash from peers on a TON DHT network and sending a message with op code op=0xd4caedcd (storage_contract_confirmed).

It seems the sender must be a storage provider to confirm and activate the storage contract deployed by the same provider.

When setting the provider as an uploader, the same role as downloader cannot be set to the provider, for example:

"active_download" : false,
"active_upload" : true,
"completed" : true,

It sounds to me the provider must download the bag and then send op code op=0xd4caedcd to the storage contract to activate it.

Original reference:

1. https://ton.org/docs/participate/ton-storage/storage-provider#info - achived creating a new storage contract and received the op code op=0xbf7bd0c1 (contract_deployed).