How to structure multi-faceted B2B software deals to protect margins?

[FrankLL]

I'm a sales director for a software company, and I'm currently leading a complex B2B negotiation with a large enterprise client that involves not just licensing fees but also extensive customization, service-level agreements, and data security commitments, and I'm finding it difficult to maintain leverage while also being a collaborative partner. The procurement team on their side is using aggressive tactics, constantly trying to unbundle our offering and pit us against competitors on price alone, which undermines the value of our integration and support services. For seasoned B2B negotiators, how do you structure multi-faceted deals to protect your margins and key terms while still closing the business? What strategies do you use to reframe the conversation around total value and strategic partnership, and how do you prepare your internal stakeholders for the concessions you might need to make without setting a dangerous precedent for future deals?