The customization of Machine Translation systems concentrates, for the most part, on MT dictionaries. In this paper, we focus on the customization of complex lexical entries that involve various types of lexical collocations, such as sub-categorization frames. We describe methods and tools that leverage existing parsers and other MT dictionaries for customization of MT dictionaries. This customization process is applied on large-scale customization of several commercial MT systems, including English to Japanese, Chinese, and Korean.