Hi First things first the television has a horizontal scan freq of 15.625 kHZ if it is used for PAL colour system ie UK or 15.750kHZ if NTSC ie USA unless it has 100Hz flicker free technology in which case it runs at twice the above freq's, so unless your card sends out TV scan rates some combined tv/video cards do you cannot use it.
VGA 640x480 at standard refresh is at 31.5kHZ horizontal and 60Hz vertical and all other modes are higher still.
Any how the connections on the 15W is as follows
1 Red signal
2 Green Signal
3 Blue Signal
4 not required
5 not required
6 Red Ground
7 Green Ground
8 Blue ground
9 not required
10 Sync Ground
11 not required
12 not required
13 Horizontal Sync
14 Vertical Sync
15 not required
also not all scart i/p will accept RGB but require composite video I hope your manual will give the connections for your scart if not searching on the net will give you what all the pins are supposed to do but it is unusal for all to be implemented.
Best Regards
R.K.Barsby