Code block syntax highlighting

Greetings and compliments of the day.

We use FOP successfully to generate nice PDF files for our technical
documentation.
Although there is one more requirement: printing formatted code blocks
with syntax highlighting (e. g. SQL or Java code snippets). What would
be the best way to achieve that?

I have tried to convert the SQL/Java code to SVG via Pygments and to
insert it as EXTERNAL_GRAPHICS. This works in general, but I cant
control the sizing. Each EXTERNAL_GRAPHICS will have a different size
of characters based on the size of the graphics.

Does anyone know a better way or has done something similar already? I
would appreciate any idea or hint.
Thank you in advance and best regards

Andreas