Organising a charity shoot ?

[taz]

I may well be tasked with helping to organise a charity shoot to raise money for a special cancer charity for children after the the young girl who started it died a couple of weeks ago at just 14yo
I have never organised a clay shoot for charity before and really don't wan't to let her down as her courage was amazing. I do have a few ideas but what I am a bit worried about is approaching companies and people to donate prizes, there are so many worthwhile charities about I'm sure many companies get a bit fed up with being asked to donate. If anyone can give me some pointers of where to go and who to ask I would appreciate it, remember it's going to be a clay shoot.
The young girl was called Faye Proudlove so far the charity has raised £5,321.00 and the target is a rather modest £50,000.00 There is a website here
http://www.justgiving.com/fayeswish
This is to me an important charity for a very special girl who showed extreme bravery as she battled a truly horrible disease, and as such I don't wan't to make an ass of myself so I really need to get this right and raise as much as possible for this truly genuine cause.
Like I say I know there is always people asking for charity help, but for me this is a first and the reason I have volunteered to help organise what I believe could be a really good day if it's done properly.
Is it worth writing to the manufacturers like webley and Scott, Ely cartridges etc and companies like that to blag some prizes ? I am going to need rafle prizes, competition prizes etc and have started making a list of things I need to do from organising the venue through to advertising etc, I intend to speak to B.A.S.C and basically involve as many people as possible, my mate works at Man UTD so he will ask the players to see if maybe one or two of them will come as there are a few that shoot.
thanks for any help in advance