EPlus says it filed the suit at a Virginia district court in April this year. Court proceedings are expected to start in March 2006.
SAP vehemently denies the charges which relate to three ePlus patents for its e-commerce software package called eECM (for enterprise cost management) that is used to source goods electronically.
Herndon, Virginia-based EPlus did not say how much it was seeking in damages from Waldorf-based SAP.
This is the second patent suit that ePlus has recently served. Earlier this year the company collected $37m in settlement against e-commerce rival Ariba Inc. The company had originally sought damages of up to $98m.
