Hi Multigus,
You can use the \v code, or use \11 as "VT" is ascii 11. Try this:
place a string control, and enter the character you want (example a
newline); then right click and select '\ code display'; this is the
code you need to sent.
This knowledgebase may help you further:
http://digital.ni.com/public.nsf/websearch/77C8F61D36F5A23086256634005ACB38?OpenDocument
To sent a "VT" you can create a string constant, select '\ code
display'; enter \11 and append this to your data.