If you use a prompt set you can can config the text value as a password.
You then get an encrypted value back on the report.
2014-01-06 14:57:54 - U0020206 Variable '&TEXTFIELD1#' was stored with value '--1088504CD34B2352F3A70CFB1C77492C8A'.
You will then need to unencrypt that value before you use it with the &UC_JOBMD command
FYI V9 did have bugs with doing this depending on which SP you were on