Translation analysis: From the standpoint of translation, the phrase "Christ - for in the last night the angel spake unto me that this should be his name" is quite difficult. McConkie and Millet in their Doctrinal Commentary on the Book of Mormon read this passage quite literally, and suggest that many titles become names, and therefore this is not that unusual.
This understanding is certainly an explanation of how Joseph Smith might have understood the title as a name, for Jesus Christ has certainly become a paired set as equivalent to a name as to a name and a title, and probably more as a name because of the general lack of understanding of what the title actually is. This is not, however, a very adequate explanation of the underlying text, as Christ and Messiah are equivalent (Christ anglicized from the Greek for "anointed" and Messiah anglicized from Hebrew for "anointed").
It is certain that Jacob was told the name, but that it was most likely the name we translate as Jesus. Later in Nephi we have similar language about name:
2 Ne. 25:19 For according to the words of the prophets, the Messiah cometh in six hundred years from the time that my father left Jerusalem; and according to the words of the prophets, and also the word of the angel of God, his name shall be Jesus Christ, the Son of God.
It would appear that Nephi is citing Jacob's revelation here, and that the "name" included the proper name Jesus. Just as with the statement "his name shall be Jesus Christ, the Son of God," it is not required that we see Christ as a name any more than we so "the Son of God."
The potential association of "Christ" as a name rather than a title is also possible from reading the King James Version of the Bible:
1 Cor. 1:2 Unto the church of God which is at Corinth, to them that are sanctified in Christ Jesus, called to be saints, with all that in every place call upon the name of Jesus Christ our Lord, both theirs and ours:
1 Jn. 3:23 And this is his commandment, That we should believe on the name of his Son Jesus Christ, and love one another, as he gave us commandment.
Other examples could be cited, but these two suffice to show the combination of the concept of "name" and "Jesus Christ."
All of this suggests that there is simply a substitution in the translation of the text, similar to the use of "adieu" as part of the translation (see Jacob 7:27).