70% convential with 30% seller finance

[Dustan Marshall]

I am interested in entering the multi family space but the cost of entry seem so much higher than the so how family units that have purchased so far.  My covnetional lender will lend up to 70% of purchase price.  And if I can get the seller to carry a second position note for up to 30% I would be able to gain ownership with little to no money Down.  Has anyone done this strategy?  If so how does it work?  Does the bank require some documents stating the other 30% is taken care of?  How do you address this?  Are you very open with conventional lender about owner carry back?