How to import HDR in UDK

[Dipnusurf]

Hello everyone!
I just want to try to import HDR texture in UDK, but according to what I found, it only accept .float format.
I have several .hdr and I'd like to know how to convert these files in .float.
I found that HDRshop does that but there is no way to find the free version.
Is there any other way to do that?

Thanks!

[jak_carver]

You can use photoshop

[Dipnusurf]

Thank you for your answer, I didn't know my HDR image has to be spherical ^^
But the problem is that I can't save in .float file format in Photoshop (CS5)
Any idea how I can do it?