Problems with using uuencode on RHEL to send mail attachment

I have a unique situation where I'm going from an AIX platform to RHEL for a vendor supported application. Within the application, I can send a command (limited to the amount of characters I can send) that will email me results of a print job.

To do this in AIX, I'm passing the following command:

uuencode temp.txt | mail -s "test"

This sends standard output to the email as an attachment named temp.txt. Temp.txt doesn't exist on the AIX server.

I have downloaded the rpm for uuencode for Linux, but it doesn't work in the same fashion. It sends an email with what looks like garbage (could be missing MIME header).

I'm looking for a similar command. To simulate outside of the application, I use the following in AIX:

echo "testing mail" | uuencode temp.txt | mail -s "test"

I know mailx -a <filename> would work if I had a filename, unfortunately I'm working with standard output vs a file.

Any help will be appreciated.