I haven't tried with Tekken, but it should be possible due some demos that require activation (NHL 08, MX vs ATV, etc) can be installed through proxy if you first "touch" the download through PSN to activate them.
i have download WH from the link in this site, upload on ps3 with ps3proxy and ... copyright error
so i have buy WH from store and STOPPED DL at 1% or a bit more and the game is full activated without dl all .pkg from store.
Activating the download on the Download List of PSN Store first, cancel the download (just after the 'activated' message or at 1% or less), copy the PSN link to download on PC, then install on PS3 using the PS3.Proxy have worked for me.
I have installed successfully PAIN, Warhawk Omega Dawn and others using this method. All them have been purchased to appear on the Download List (otherwise they will not work). Same with demos that require activation, like MX vs ATV and NHL08.