problem with delete when multiple columns

Question

hiya

when deleteing this works:

orderitems.Delete(x => x.orderitem_sessionid == transkey);

however this does not work

orderitem.Delete(x => x.orderitem_sessionid == transkey 
                       && x.orderitem_productid == 6);

i get no errors, but nothing is deleted either, i have working code as a substitute of

var DeleteableItems = orderitems.All().where(x => x.orderitem_sessionid == transkey 
                                             && x.orderitem_productid = 6);

foreach(var item in DeleteableItems) item.delete;

though the above works it still bugs me that this wont work with just nomal delete method, using subsonic 3.0.0.3 and mysql database

thanks