docbook fo w/ fop 0.20.5 errors

I try to convert a .fo file to PDF using the standard FO generated by most 
recent docbook stylesheets.

Using fop 0.20.5:

fop  sample4.fo sample4.pdf

I get the following two fop errors (multiple times each):

[ERROR] Unknown enumerated value for property 'relative-align': baseline
[ERROR] Error in relative-align property value 'baseline': 
org.apache.fop.fo.expr.PropertyException: No conversion defin
ed

AND

[ERROR] property - "background-position-horizontal" is not implemented 
yet.
[ERROR] property - "background-position-vertical" is not implemented yet.

Is there any workaround for this?

Michael Piastro