I don't think the fibers would work well in mp since it won't dissolve. The heat of the lye solution is what dissolves the silk fibers. I think it would most likely just clump up in mp. I don't have any experience adding liquid silk to soap of any kind, but maybe someone here has and can advise.
The liquid silk is perfect for water based products such as lotion and emulsified scrubs and small amounts can also be added to melt and pour soap. Tussah silk fibers can be dissolved in your lye solution and added to cold process soap.
But this is for melt and pour which means the op is unlikely to have the lye solution. I have seen your other posts - why not pop in to the "introduction" section and tell us more about yourself, as some of your posts are a touch spammesque in nature