The problem(or at least for me) only happens when you set double buffer.
If i were you i would make remove own_window, and remove double buffer. It will flicker occationally, but it will look like this.
http://img91.imageshack.us/img91/2482/bsdtorsmo4el.png
EDIT: Ok, i have come up with a better method.
1. Download and install a program called devilspie.
2. create a file ~/.devilspie.xml containing this.
Code:
<devilspie>
<devilspie>
<!--
Hide Torsmo From the Taskbar
-->
<flurb>
<matchers>
<matcher name="DevilsPieMatcherWindowName">
<property name="application_name" value="Torsmo"/>
</matcher>
</matchers>
<actions>
<action name="DevilsPieActionHide">
<property name="skip_tasklist" value="TRUE"/>
</action>
<action name="DevilsPieActionHide">
<property name="skip_pager" value="TRUE"/>
</action>
<action name="DevilsPieActionLayer">
<property name="above" value="FALSE"/>
</action>
</actions>
</flurb>
</devilspie>
3. run devilspie
4. Edit your torsmorc to have own_window yes
5. Close all running windows.
6. Run torsmo with double buffering(-b or in the config)