• Create a parameterized job
• Add a textbox parameter (e.g. Comment = ABC newline BCD)
• Add a build action: Inject environment variables, in the content field override Comment to e.g. $WORKSPACE
• Add a shell/winbatch an prompt 'Comment'

plugin version 1.89 console:
[EnvInject] - Variables injected successfully.
new comment value = ${WORKSPACE}
plugin version 1.90 console:
[EnvInject] - Variables injected successfully.
new comment value = ABC

Assume the property 'Comment' is not overwritten anymore.

My personal problem:
I want to give a multiline value via build parameter to an ANT but because of the newlines i permanently get a syntaxerror, so i decided to print te parameter to a file, and give the file to the ant instead.