Pronunciation in AI Audio (TTS)

I am hoping someone can clarify the use of SSML with Eleven Labs voices in Storyline 360. I've read variously on E-Learning Heroes that SSML is not supported with Eleven Labs voices or that it is supported but only for <phoneme> and <break> or it's supported for other tags too. I've been trying to use it with the phoneme tag but when I generate speech, it simply skips over the tagged content.

This is a sample of one use I'm trying to get to work:

Repair of this injury can be addressed laparoscopically in stable patients. The first priority is adequate exposure. Additional ports should be placed as needed to isolate the injury and improve visualization. If the bowel is friable it can be handled indirectly using <speak><phoneme alphabet="ipa" ph="æ.tɹ.ə.mˈæɾɪk">atraumatic</phoneme></speak> graspers on the mesentery, and the edges of an enterotomy can be approximated to limit contamination if the injury is small.

When generated, all the speech between the opening <speak> and close </speak> tag is simply skipped but the rest of the speech is rendered. Since I am not sure if SSML is even supported, I'm not sure if I'm not rendering the tags correctly, or if it simply isn't supported.