Using what you had, here's an update to get the 3rd line as well:

Code:
if (Twitter Update isin $strip($1-)) && (!%twitter.updated) {
  echo #newbox $1-
  set -eu5 %twitter.updated 1
}
elseif (%twitter.updated) {
  echo #newbox $1-
  if (%twitter.updated == 2) { unset %twitter.updated }
  set -eu5 %twitter.updated 2
}
elseif (http://twitter.com/ScoobeeDoo isin $strip($1-)) { echo #newbox $1- }

Invision Support
#Invision on irc.irchighway.net