Vyatta - Enable WebSafe search for entire School

My School's ICT director want to block all adult content from Search result (almost google). Here's how from google, there are 3 options:
1st option turn on safesearch which require a google account on every Chrome
2nd option require Chrome book
3rd Option which work for entire network without edit every single machine -> I go this way ^^

With our school infrastructure in place: Vyatta black box outside the border and local DNS server
Step1: redirect all https://www.google.com https://www.google.com.vn -> http://nosslsearch.google.com
Because google turn on https by default so all the content was encrypted so that it cannot be filtered out, I have to redirect the search result to other nosslsearch which also provide by Google.
In our DNS server which running Windows Server 2008 RC2 (I hate them but it were there before I come :D )  -> create 2 Primary DNS zones www.google.com, www.google.com.vn
Add a CNAME record: leave the alias name as blank, add FQDN nosslsearch.google.com. as target host
Right Click on the DNS server -> Clear Cache
==> All the request to https://www.google.com will come to http://www.google.com which will not affect any other Google product require ssl (drive, gmail, plus...)

Step2: append &safe=active directly to all search URLs which happening on Vyatta black box.

configure
set service webproxy url-filtering squidguard enable-safe-search
commit
save

enable-safe-search: turn on safe search for almost search engine

The final result: when I search Sex on my search box

http://www.google.com.vn/search?q=sex&safe=active&hl=en&noj=1&source=lnms&tbm=isch&sa=X&ei=SrOWU_muPNHp8AX0y4CIAQ&ved=0CAgQ_AUoAQ&biw=1366&bih=638

The result I always dislike but it good for the kid :D