There is no canonical answer, but three things can be inferred from the three-episode arc.
Surak is not Google
Surak is not seen in this arc imparting encyclopedic knowledge to Archer - it is a conversational sharing of wisdom. While it is shown to be extremely taxing on Archer and not on Arev, it is impossible to know exactly how draining it is for a Vulcan to communicate with a Katra. One would presume that it is just as taxing as it is on a Human, but Vulcans just do not show it. Simply asking Surak for the translation may be far to mentally taxing to be practical.
The artifact is a holographic device storing data on a microscopic scale, and it is huge. It is implied by the series that it is a huge amount of text. Additionally, translation of text of this sort takes a careful hand. Authors of philosophical texts usually have precise word choice. Translating such a text is not just a matter of substituting one language's words for another, but of translating the meaning of a word or phrase. That would require understanding the text in its native language first. It would just be too long for Surak to just tell T'Pau the meaning of the text, and have her be the sole source of translation.
Where is the discipline?
Spending time to understand a work well enough to translate it requires a great deal of discipline and attention to detail. Just being told what it means is not nearly as valuable as discovering what it means. The Katra of Surak's stated goal was for Vulcan to re-discover (his brand of) logic.