I am going to apply at swiss embassy. Must i give my old passport where i have my previous visa to shengen country? My new passport has been renewed in Brussels Belgium while i was in Portugal because we don't have embassy in portugal. If i don't include that passport, will they anyhow know about my first visa? Will i be considered as overstayed? My payslip and proof of tax payment to portuguese government will not help at all on this scenario?
Note: I lived and worked legally in portugal under article 88.