Maven Execution - Executable Not Found

I have a maven pom that has an executable defined as such

<execution>
     <id>generate-build-number</id>
     <phase>prepare-package</phase>
     <goals>
          <goal>exec</goal>
     </goals>
     <configuration>
          <executable>git</executable>
          <arguments>
               <argument>log</argument>
               <argument>--pretty=format:buildNumber = %H</argument>
               <argument>-n1</argument>
          </arguments>
          <outputFile>${project.build.directory}/build-number.properties</outputFile>
     </configuration>
</execution>

I get the following error:

[ERROR] BUILD ERROR
[INFO] ------------------------------------------------------------------------
[INFO] Result of /bin/sh -c cd /cvs/nexus/cms && git log '--pretty=format:buildNumber = %H' -n1 execution is: '127'.

and in my build-number.properties file I get the following

/bin/sh: git: command not found

I'm able to run the same Maven lifecycle command from the command line just fine.  Is there a way I can set the path for the git command somewhere?  Any help would be greatly appreciated.  Thanks.