Hello Natalia,
you should be able to post the consumption from the silo. Prerequisite is that the UI for the consumption finds the stock on the PSA. For a silo, the bin that represents the silo needs to be assigned to the PSA in transaction /SCWM/PSASTAGE or /SCWM/PSASTAGE2. If your silo is an HU from the system point of view (= multiple silos, you choose one at GI), those HUs have to be placed on the bin from these transactions.
Best regards,
Katrin