How do I use return codes from ftp node?

I have a series of ftp nodes in an IPA flow. On the error tab the below variables exist.

 

Error code:
Information code:

Return message:

I would like to use these to test for successful transfers but do not see them in an assignment node Ctrl-Space list of variables. I tried removing the but still cannot assign them.

Is there a way to use these error codes in subsequent nodes?