using external IR in space designer

[elan]

hello

i often find IR which are 2 stereo files, labeled L and R.

how i can use them in space designer?

it has some true stereo IR which are supposed to be a single file with 4 tracks 2 for L and 2 for R

how can i make this kind of file?

i need to join the L and R together in a single file, because SD don't accept two files, but can manage files of more than 2 tracks (like the surround ones)

thanks