The Tigers were working far beyond Tuesday's 11pm deadline to try to confirm the signings of Salibur and Kamil Grosicki, with only the Poland winger's arrival ultimately finalised in time.
The suggestion was that the paperwork for the Salibur deal was not submitted in time, but Hull have appealed to FIFA in an attempt to force through a reported £9million move.
Silva said: "We are still waiting. Up to now, we don't have the final decision of FIFA.
"When we have, we will let you know. We don't have a date."