How to ignore output from executable with CruiseControl.Net build?

I'm running a little find and replace utility called fart.exe (yes, fart, as in Find and Replace Text) as part of my CC build. Works great.

The problem is that FART while it is working displays a little ASCII spinner composed of pipe, dash, slash... | / - . There isn't a way to suppress this spinner, and CC thinks these little symbols are error messages and the build fails. I've tried:

adding those symbols as successexitcodes in CC -- same result, apparently only ints work
Calling fart via a batch file with ECHO OFF -- it still outputs the spinner and causes the build to fail

Any other ideas?

<exec>
<executable>C:\fart.exe</executable>
<buildArgs>myfile.txt string1 string2</buildArgs>
<successExitCodes>1,0</successExitCodes>
</exec>

Solution

Thanks for the answers, but I ended up doing two things:

Recompiled the text replacement app (fart) without the spinner. Even after doing this CC was still failing for some reason, so I...
Moved batch executables to the msbuild file instead of cc config file. CC then built successfully.

I'm sure if I understood CC better I could have gone about this better way but for now this does the trick!