with 28mm aspheric (DX SKU 5297), pressure switch from MF http://www.manafont.com/product_info.php/pressure-switch-for-ultrafire-501b-flashlight-55cm-p-4991 and Universal Mount (DX SKU 5819).
I blanked the reflector with a black paper cone (gets rid of nasty artifacts). It throws a great spot out to ~200m.
The Cree XR-E R2 is the biggest thrower among all lights (XR-E, XP-E, etc) the other variables are just how hard it's driven and how large the reflector/optic diameter is.
Artifacts are things like rings or even worse the "disco ball" effect. I don't know of a link to a picture right off the top of my head.
A SMO reflector will throw further than an OP but if you are using an aspheric lens you don't want a reflector as that causes the "disco ball" effect and does nothing for throw when using an aspheric.
In many lights you can't removed the reflector since the light is using it as a spacer to keep the pill in place. If the pill is screwed in to the body of the flashlight you can just remove the reflector. Otherwise you need to remove the effect of the reflector. You can do this by painting it flat black or as others have suggested try putting a piece of cone shaped black paper in the reflector.
If you aren't going to be using this light in any way other than as an aspheric just paint the reflector black.
I don't have that particular light but I assume it's a standard P60 light. I've had a P60 light in the past with which I used that aspheric and it is at the correct focal length when used as a direct replacement for the standard glass lens so you should be fine.
When I did the same thing you are trying to do it took me just minutes. I just painted the reflector and put it back in the light, switched out the flat glass lens for the aspheric and screwed everything back together and I had a thrower!
You can make the beam look even better if you want to do a little more work but you may not find it necessary. I eventually ended up painting out the "Cree ring" as well. If you get a small bit of paint on the base of the dome while doing this you can take some Scotch "Magic" tape and from the flat side of the aspheric lens mask off only the outer edge and this will eliminate any artifact created by any paint you might have gotten on the base of the dome.
You don't need to do any of this if you don't want to however so the basic conversion is easy. I'm just giving you more details if you find if helpful after you've received this light.
I'd use flat black spray paint and give it two coats. You'll have that outer ring unless you use a small hobby brush and also paint out the silver ring around the emitter. Your call on that one. I did it and it works.