Not trying to complicate the issue here; I want to help you guys succeed. My advice is worth what you've paid for it.
Also bear in mind that at law school we get taught to find problems, not always how to solve them.
The trouble element I see is that at the end of the contract the principal ends up being the owner of the hardware. At some point during the contract metabank.ru must own the hardware (even though they do not have privity to the contract), the question is does BitCentury become the owner at some point before the end of the contract? I think the answer to that is probably yes (invoices etc would be in BitCentury's name, not the name of the principal), in which case it gets harder to deny that you are not performing a sale of goods contract.
Hopefully your lawyer will either spot the flaw in my argument or be able to amend the contract to protect you, but like Dogie says you want to be careful that you don't end up with something that ends up being interpreted as a contract of sale of goods.
I last studied contract law 3 years ago, my analysis might be off. Sorry if bringing this up ends up being a waste of your time.