skype codec choice

I recently found that my UK calls are using PCMU. So with bad Internet calls dropped. Found a way to disable PCMU from a forum post and other sources. In ~/.Skype//config.xml:
<config>
<lib>
...
<call>
...
<disablecodecs> SILK_V3 PCMA PCMU </DisableCodecs>
</Call>
...
</lib>
</config>

For windows see this blog post.

Unfortunately this didn't help because chosen codec is g729 what I wanted but I hear only silence from the remote end. Disabling g729 makes call fail.

P.S. thanks to this guy and this tool for the xml encoding above