anyattribute ##other?

[thomas smith]

hi all,

I have a question with respect to anyAttribute functionality. Consider
the following XML excerpt

<?xml version="1.0" encoding="UTF-8"?>
<object xmlns="urn:foob" xmlns:it="urn:foo:it"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
.....
<item param="value1" it:test="value2"/>
.....
</object>

now, my schema needs to express/restrict that

1. the item element (in the urn:foob NS) has a required attribute
param (no NS prefix required).

2. the item element (in the urn:foob NS) can have multiple optional
attributes (anyAttribute) from a NS other than urn:foob. These
attributes must have a NS prefix.

Note that using anyAttribute="##other" is not sufficient, as this
still allows to add attributes without NS prefix.

can someone help me ahead with this problem?
many thanks
thomas