How to configure space after a block that spans multiple columns?

I'm using Apache FOP 2.9.

I have a two column layout that's frequently interrupted by blocks that span all columns.

All text appears in the correct columns, but the space-before and space-after attributes are ignored. What's the correct way to add spacing after a block that spans multiple columns?

<?xml version="1.0" encoding="UTF-8" ?>

<fo:root xmlns:fo="http://www.w3.org/1999/XSL/Format">
    <fo:layout-master-set>
        <fo:simple-page-master master-name="two-col">
            <fo:region-body column-count="2" column-gap="1cm"/>
        </fo:simple-page-master>
    </fo:layout-master-set>

    <fo:page-sequence master-reference="two-col">
        <fo:flow flow-name="xsl-region-body">
            <fo:block span="all" space-after="1cm">
                Span all.
            </fo:block>
            <fo:block space-before="1cm">
                Left column.
            </fo:block>
            <fo:block break-before="column" space-before="1cm">
                Right column.
            </fo:block>
        </fo:flow>
    </fo:page-sequence>

</fo:root>

I've dealt with the same issue, space-befores and space-afters don't work as expected when you switch from span="all" to span="none" in Apache FOP. Use an explicit 1cm block-container to separate the two areas.

<fo:flow flow-name="xsl-region-body">
    <fo:block span="all">
        Span all.
    </fo:block>
    <fo:block-container span="all" height="1cm">
        <fo:block> </fo:block>
    </fo:block-container>
    <fo:block>
        Left column.
    </fo:block>
    <fo:block break-before="column" >
        Right column.
    </fo:block>
</fo:flow>