NMap scanning from ethernet lan to wifi part

[brabo <brabo () nrgsports be>]

Hi,

This is the setup: 1 ethernet/wifi router with 3 wifi clients connected to it.
1 ethernet router with wired connectien
3 pc,s behind the last router.

now, when i start an nmap scan of the subnet of the ethernet/wifi
router, all i detect is the router itself.
so, none of the wifi-connected pc's show up. is this normal?
is there a way to see those clients?

router model is SMC2804WBR.

Thanx for any input,
brabo.

-- 
Microsoft isn't evil, they just make really crappy operating systems.
-- Linus Torvalds