If I understood correctly, you need to correct your code in a following way:
2 = TMENU
2 {
wrap = <ul class="naviMainLevel2"> | </ul>
NO {
wrapItemAndSub = <li> | </li>
}
ACT = 1
ACT {
wrapItemAndSub = <li class="active"> | </li>
#parameter.override.field = tt_news_id ||uid
# ^ you don't need this line, becasue you still need
# the current page id in url and it shouldn't be overriden
# by some other param
# next you need to get current tt_news uid from GET
# as you mentioned in your comment
additionalParams.data = GP:tx_ttnews|tt_news
additionalParams.intval = 1
additionalParams.wrap = &tx_events_pi1[newsUid]=|
}
CUR = 1
CUR < .ACT
}