Hi,
For example: I chose one of the .ts files from Sigil-0.9.3 and opened it and searched for "Binding designer" and found the following.
Code:
<message>
<location filename="../../BookManipulation/Metadata.cpp" line="352"/>
<source>Binding designer</source>
<translation>Diseñador de la encuadernación</translation>
</message>
So most if not all of these entries should be already be translated and just need to be moved slightly. If it would help, I could write python script to extract them into some form you can import into the translation software in some way.
Just let me know and I will pull something together to try to automate the process.
KevinH