Who said it can’t be done? Last Saturday I went to Brandywine Creek State Park to experiment a little with Infrared Photography (see my other three pictures starting here) Those three were taken using an old Nikon CoolPix 950 and Wratten filters (87C, to be precise). This photo here was, on the other hand, taken with a Canon 20D with a Sigma 15-30mm lens, which has a back end slot for gelatin filters, and I used a Kodak Wratten 89B filter. I understood you could not take IR pictures with a 20D but I guess all is in the patience you put in something to achieve what you want.
The original picture, as it came from the camera, is to your right (click on thumbnail). Picture was cropped, converted to Lab, discarded channels A and B and you are left with the Lightness Channel to work with. A Level and Curves adjustment did the rest.