form by eck__entity__add, but can not be used to create new content , did i miss something ?

I use eck to define a new entity,
but different from node/add/article,
when i use entity_type/add/bunble_name,
can not see the content-add form,
then some one tell us to use hook menu, and
return a form return by eck__entity__add,
then we can see the form with custom content-add-url,
but
1, we can not use hook form alter to change values in form element
2, when we click save, but can not save data,

so may i ask if I miss something, or eck currently only for enitities that save data.

Regards.