The workaround is to add the transactions manually using the LP-token as outlined before.
As long as this token is not listed on any price source you need to add a custom price (see "non listed asset" FAQ).
If you add the fee correctly as described in the FAQ they are subtracted from the balance of course.
Thank you! I appreciate the prompt responses to my questions (despite there being a lot) and will be in touch again if any further questions come up. Thanks again, you rock!