The petitioning U.S. entity files Form I-129 and pays the government amounts in the current USCIS fee schedule, Form G-1055. Arrangements that shift those costs onto the employee, or that have a third party pay the salary, undermine the structure the petition describes.
Who pays is also evidence about who employs
Hypothetical example: the contract manufacturer offers to pay part of the specialist's salary while she is on their site, which would save the affiliate money and damage the petition. The requirement that the placement not be labour for hire is supported by ordinary facts: the petitioner pays her, directs her and evaluates her. Keep the money flowing that way and let the third party pay the company under the services agreement.
Budget separately for immigration representation, certified translations, relocation and any duplication of her Coaldale duties while she is away. Where the assignment involves travel between the affiliate and another site, decide in advance who books and reimburses it. Check the current G-1055 schedule rather than relying on an amount quoted in an older document, because those figures change.