Mapped property inside a mapped property is not populated on submit

Hi, everyone.

Suppose, I have a Map in my form, called "person":

private Map person;

That Map has (besides other entries), a entry called "addresses", which is in
turn a Map again. This "addresses" Map has several addresses of the person. One
of those addresses has key "home" and String value of home address.

I want to render a text input field for the "home" address - I use EL syntax, no
brackets (it renders element correctly):

<nested:text property="person.addresses.home"/>

In html this element is being rendered correctly, including correctly
displayed value of home address, taken from the "addresses" Map.

However, if I submit this form with changed value of address, it's not being
populated.

I wrote my own implementation of "addresses" Map to see what's happening, and I
saw that no put method is called at all (only get() while rendering the element).

So then I also made custom implementation of "person" Map and saw there, that
while submitting, it calls get("addresses") (which returns "addresses" Map) and
that's all.

So apparently, BeanUtils sees, that it retrieved a Map and stops processing, not
generating any exceptions BTW.