Interesting question.
The CRB only talks about PANs:
Programs and devices attached to the PAN appear as smaller representations of their normal icons, carried by the persona.
The question that springs to mind is; does slaving the PAN of one user to a device like a cyberdeck create a new PAN?
If the answer to that is yes, then the icons of the samurai's PAN "appear as smaller representations of their normal icons, carried by the persona" of the decker.
I think the answer is no, to be honest, because the samurai is still running a persona that his PAN is attached to. The icons may be hidden by virtue of being protected by the decker, but ultimately, the samurai's PAN and his icons are still attached to his persona and so would appear near the device his persona is formed on.
In other words; if someone makes a Matrix Perception Test (Electronics + Intuition) and beats their opponent (Willpower + Sleaze) then the previously hidden persona and icon(s) are revealed.
If you think of the persona as the "wireless signal" (p 178), then all a hacker is doing is obscuring that signal and hiding it in the overall data stream of the Matrix. He's not actually subverting the icon into his own persona.
Or am I massively overthinking this? I just feel that if all it takes to completely and utterly hide your icons from Matrix Perception is to slave it to a decker 1000 miles away, then the rules serve no purpose. The alternative option is to treat hiding in the Matrix like hiding in the physical world; your Stealth roll hides you while you move, but if an observer beats your roll with their Perception roll then the jig is up and you are spotted.